Non-Surgical · Contour Injection · Safety

Side Effects and Safety

What to expect after a fat dissolving injection, and what to report

Gangnam, Seoul | Board-certified plastic surgeon, Dr. Jonghwan Choi
KHIDI-registered for international patients · Apgujeong Rewind

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Safety

Side effects, in proportion

What are the realistic side effects of a fat dissolving injection?

The short answer

Swelling, a stinging soreness, bruising, tenderness and numbness over the treated area are the expected reactions, and most settle within days to a few weeks. Rewind's own aftercare sheet describes light swelling that generally improves within two to three days. Less often, firm lumps form under the skin and soften over weeks, or one side responds faster than the other. Rare but documented problems after deoxycholic acid injection include skin injury at injection sites, temporary weakness of the nerve that moves the lower lip, and difficulty swallowing.

Sources: Rewind's Korean treatment page and aftercare guidance; the US prescribing information for the approved deoxycholic acid injection; a 2024 systematic review of serious adverse events after deoxycholic acid injection under the chin and jowls.

Two points put that list in context. The expected reactions are part of how the treatment works: a preparation that breaks down fat cells causes local inflammation, and inflammation swells and aches. The rare problems are mostly about where the needle goes. They are the reason placement, depth and knowledge of the anatomy along the jaw matter more than anything written on the vial.

The published figures on this page come from studies of deoxycholic acid, a drug in this category with large placebo-controlled trials. Rewind's contour injection is a separate preparation whose ingredients are disclosed at consultation. The figures are therefore a guide to the category and not a forecast for any single product or patient.

Dr. Jonghwan Choi examining a patient at the consultation desk
Fig. 01 · Safety starts with deciding whether an injection is suitable at all
Scale

How often, how serious

Fat dissolving injection side effects, sorted by how often they are reported

In the pooled placebo-controlled trials of the approved deoxycholic acid product, reactions at the injection site were very common and mostly short-lived. The tiers below follow that record and the clinic's own aftercare notes.

tier 01
Expected
Swelling, bruising, pain, numbness, redness and firmness at the site. In the approved product's trials each of these affected more than one in five treated patients.
tier 02
Common, short-lived
Tingling, itching, small nodules and a tight feeling in the skin. These usually fade as the treated fat is cleared over the following weeks.
tier 03
Uncommon
Nerve injury producing an uneven smile was reported in about four percent of treated patients in those trials, and every case resolved on its own. Difficulty swallowing also occurred and resolved.
tier 04
Rare and serious
Skin ulceration or tissue death at injection sites, hair loss in the treated area and injury to nearby vessels are listed as warnings in the labelling and discussed in the 2024 review.

These percentages come from the US prescribing information for the approved deoxycholic acid injection and describe that drug in trial conditions. They are cited here to show the shape of the risk, not to predict what one person will experience.

Cause

Why they happen

Why a fat dissolving injection causes the side effects it does

Knowing the cause of each reaction makes it easier to tell a normal course from a problem.

01Action

The preparation acts on cell membranes

A 2010 laboratory paper reports tissue-selective effects of injected deoxycholate: this helps explain why fat is the intended target. The same action explains why depth matters, since skin, muscle and nerve are only millimetres away.

02Inflammation

Clearing fat produces swelling and firmness

Broken-down fat cells are cleared by the body over weeks. That clean-up is inflammatory: the area swells, aches and can feel firm or lumpy before it settles.

03Anatomy

A nerve runs along the lower jaw

The marginal mandibular nerve, which moves the lower lip, lies near the border of the jaw. Labelling for the approved product tells injectors to keep away from it; injury shows as an uneven smile.

04Placement

Serious events trace back to where the needle went

The 2024 systematic review describes skin injury and vascular problems after deoxycholic acid injection and sets out how each should be managed. Injecting too shallow, too close to a vessel or outside the mapped area raises that risk.

Consultation room at Rewind Plastic Surgery, Gangnam, Seoul
Fig. 02 · Anatomy, medication and past treatments are reviewed before the treatment room
Rewind

Why here

How a plastic surgery setting lowers the risk of a fat dissolving injection

Most of the risk in this treatment is decided before the first injection. Three habits at Rewind address it directly.

01Mapping

The layer is read first, injected second

Rewind uses an ultrasound scan to read fat thickness, deeper fat and the salivary gland. An injection placed into confirmed superficial fat is an injection kept away from gland, muscle and deep structures.

02Anatomy

The injector operates on the same region

Dr. Jonghwan Choi performs surgery under the chin and along the jaw, so the course of the nerve along the jaw border and the vessels in the area are familiar ground.

03Follow-up

The person who injected you reviews you

Concerns after treatment go back to the doctor who planned the injection. That shortens the time between a warning sign and someone who knows exactly what was done.

Private consultation space at Rewind Plastic Surgery, Apgujeong
Fig. 03 · Questions about ingredients are answered here, before booking
Checks

Before the first injection

Safety checks built into a contour injection appointment at Rewind

Private lounge on the clinic floor at Rewind Plastic Surgery

Fig. 04 · A private lounge on the clinic floor

Recovery room at Rewind Plastic Surgery, Apgujeong

Fig. 05 · A private room for a quiet moment before leaving

The consultation covers medication, bleeding tendency, past treatments in the same area, swallowing and pregnancy. The area is then read with ultrasound, and fullness that turns out to be gland, lymph node or deep fat is not injected. Rewind states that its contour injection contains no steroid, uses no anaesthesia and needs no stitches. The product is identified at consultation, and you are welcome to ask to see it before treatment.

Medication and bleeding history taken
Past treatments in the area recorded
Ultrasound read of fat, deep fat and gland
Stated by the clinic to contain no steroid
Product identified before injection
Follow-up with the same doctor

If you are unsure about anything on this list, say so at booking. A question asked before the appointment is easy to answer, and some of these answers change whether an injection is offered at all.

Rates

Price and safety

Contour injection cost at Rewind, and what the fee should include

A safe appointment and a cheap appointment are measured differently. The published figure below covers the examination, the ultrasound reading, the injection and the follow-up with the same doctor.

Contour injection, 15ccOne appointment at the published volume, including examination and review
₩150,000

Whatever you pay, the safety questions are the same: what the product is, who is injecting, whether the area was assessed, and who you call if something changes afterwards. A quotation that cannot answer those four questions is incomplete.

List rate before VAT. The rate list folds any anaesthesia fee into its figures, and this injection involves none. A larger volume, where justified, is confirmed at the consultation.

Who not

Suitability

Who should not have fat dissolving injections, or should wait

Some of these points come from the labelling of the approved deoxycholic acid product; others are standard precautions for any elective injection. Each is discussed before a plan is made.

Advised against, or postponed

  • Current or past difficulty swallowing, which the labelling advises avoiding treatment with
  • Infection, inflammation or broken skin at the site, until it has fully healed
  • Fullness from an enlarged thyroid or swollen lymph nodes, which needs a different assessment
  • Pregnancy or breastfeeding, when an elective injection is put off

Treated with caution, after discussion

  • Anticoagulant or antiplatelet medication, or a clotting disorder, because bruising and bleeding are more likely
  • Previous surgery or injections in the same area, where scar tissue can change the landmarks
  • Loose skin or prominent muscle bands, where reducing fat may leave the outline worse
  • Fullness that is mainly gland or deep fat under the muscle, which an injection does not reach

When the answer is no, the reason is explained at the same appointment, and where another treatment fits better it is named.

Signs

After the injection

Warning signs after a fat dissolving injection, and when to call

Most of what happens in the first days is expected. These cards separate the ordinary from the reasons to get in touch.

First days
Expected
Swelling, soreness, bruising and numbness. Follow the clinic's rules: no alcohol, sauna or hard exercise for one day, and no rubbing or pressing the area.
First weeks
Usually fine
Firmness or small lumps that are slowly softening, and numbness that is fading. Mention them at the review.
Any time
Call the same day
Skin that darkens, blisters or breaks down, pain that keeps increasing, an uneven smile, or trouble swallowing.
Any time
Seek urgent care
Fever with spreading redness, or difficulty breathing. Contact the clinic as well, so the doctor knows what was injected.

Rewind's aftercare guidance describes light swelling and stinging that generally ease within two to three days, and allows daily life straight after the appointment. Anything outside that pattern is worth reporting early, while it is easy to assess.

Doctor

Professional

At Rewind, one board-certified plastic surgeon carries every case — from the first consultation to the final follow-up. Because a face is a story, and a story deserves a single author.

Dr. Jonghwan Choi, board-certified plastic surgeonRewind,
Dr. Jonghwan Choi presenting at an academic session
Fig. 06 — Academic presentation

Rewind's Doctor

Dr. Jonghwan Choi Medical Director

One surgeon, from the first
consultation to the last follow-up.

A board-certified plastic surgeon devoted to anti-aging lifting — with the precision and restraint built through years of craniofacial practice.

Board-certified plastic surgeon (Plastic Surgery)
10 peer-reviewed publications
Medical Director, Rewind Plastic Surgery
Korean Society of Plastic & Reconstructive Surgeons
Former chief director, Apgujeong Y&T Plastic Surgery
Korean Society for Aesthetic Plastic Surgery
J Craniofac Surg · JKMS · Arch Craniofac Surg
Korean Cleft Palate-Craniofacial Association
Ask

Questions

Fat dissolving injection safety: questions to ask ahead of booking

What are the realistic side effects of a lipolytic injection?
Swelling, soreness, bruising, tenderness and numbness are expected and usually settle within days to weeks. Firm lumps and uneven response are less common. Rare documented problems include skin injury at injection sites, temporary nerve weakness affecting the smile, and difficulty swallowing.
Do contour injections contain steroids?
Rewind states that its contour injection contains no steroid. Preparations sold under this name are not all the same, so the useful step is to ask for the product to be identified and shown to you before treatment, which Rewind does at consultation.
What should I ask before agreeing to an injection?
Ask what the product is, whether it contains a steroid or other additives, who will inject it, how the area will be assessed, and who to contact afterwards. Ask what published evidence exists for that specific preparation.
Who should not have fat dissolving injections?
People with current or past difficulty swallowing, infection at the site, or fullness from thyroid or lymph nodes should not proceed. Pregnancy and breastfeeding postpone treatment. Blood thinners, clotting disorders and previous treatment in the area need discussion first.
Can a fat dissolving injection damage a nerve?
It can, rarely. In trials of the approved deoxycholic acid product, nerve injury causing an uneven smile affected about four percent of treated patients, and all cases resolved on their own. Injectors avoid the nerve that runs along the lower jaw.
Is a lump after the injection normal?
Firmness and small nodules are common in the weeks after treatment and usually soften as the treated fat clears. Do not massage them. A lump that keeps growing, is hot and painful, or sits under changing skin should be checked the same day.
When should I contact the clinic urgently?
If the skin darkens, blisters or breaks down, if pain keeps increasing, if your smile becomes uneven or swallowing becomes difficult, or if you develop fever with spreading redness. Early assessment makes these problems easier to manage.
Does the price of an injection tell me anything about its safety?
Not on its own. Rewind lists one appointment at ₩150,000, with VAT added, including the examination and review. At any price, check the product, the injector, the assessment and the follow-up.
Voices

Google Reviews

What our patients say.

G 5.0 ★★★★★ 51 Google reviews · Rewind Plastic Surgery, Apgujeong — live-synced from Google Business Profile
★★★★★

Came to REWIND to get my facial treatment and i'm absolutely obsessed about it💞 the doctor is so kind and is an expert! Everyone must visit!

YunHee Hong2 weeks ago
★★★★★

There are just way too many cosmetic clinics in Korea and I'm so happy I found Rewind Clinic in Gangnam. Dr. Choi was so kind and patient while explaining the different face-lifting options, from threads to mini-lifts to deep-plane lifts…

J. S.5 months ago
★★★★★

I found Rewind clinic through a Korean chat forum and many local clients highly recommended it. The clinic is brand new, featuring large, clean rooms and many private waiting areas so it doesn't give off that "factory" clinic vibe. All the…

J. Siou5 months ago
★★★★★

Really nice environment. Doctor is easy to communicate and understands my visions. Waited two weeks to make a review and I confirm the results exceeded my expectations and I am super happy with it. Can't wait to come back!! :))

Kristie Chu5 months ago
★★★★★

I received a thread lift at Rewind Plastic Surgery. The clinic was clean and the atmosphere was comfortable. The consultation was thorough, and I felt confident because they kindly explained everything tailored to my facial condition. They…

한주연2 weeks ago · Translated by Google
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Scientific evidence

Evidence on fat dissolving injection safety: trials, tissue effects and adverse events

The 2024 systematic review gathers serious adverse events after deoxycholic acid injection under the chin and jowls and recommends how to manage them. The 2022 review questions the risk profile of phosphatidylcholine and deoxycholate injection. The pooled analysis reports outcomes and safety from two European placebo-controlled trials of deoxycholic acid. The 2010 laboratory study examines how selectively injected deoxycholate acts on different tissues. Percentages quoted on this page come from the US prescribing information for the approved deoxycholic acid injection. None of this work was carried out at Rewind Plastic Surgery or with its own contour injection.