The short answer
Botox can make some faces look smaller, but only in a specific way and only for a specific reason. When the lower face looks wide because of a large masseter muscle, jaw Botox may make the jaw area look narrower over time. It does not shrink bone, remove fat or change the overall size of your head. Understanding where facial width comes from is the best way to know whether masseter treatment could help you.
Where facial width comes from
When someone feels their face looks "big" or "wide", the impression usually comes from a mix of factors:
- Muscle.
The masseter, the main chewing muscle at the back of the jaw, can be naturally large or become bulky with clenching, grinding or frequent chewing.
- Bone.
The width and angle of the jawbone and cheekbones set the basic frame of the face.
- Fat.
Fullness in the cheeks, along the jaw or under the chin adds roundness.
- Skin and support.
As skin loses firmness, the jawline can soften and the lower face may look heavier.
- Proportions.
A short or recessed chin can make the lower face look wider relative to its length.
Masseter Botox only changes the first of these. If muscle is a major contributor, the change can be noticeable. If bone or fat dominates, the change may be small.
How a doctor checks whether masseter Botox may help
A consultation for jaw slimming usually includes a simple physical check:
- Clench test.
You clench your teeth while the doctor feels the angle of the jaw. A firm, bulging muscle suggests the masseter contributes to width.
- Front and angled views.
The doctor looks at how wide the lower face is compared with the cheeks and forehead.
- Habits.
Questions about grinding, clenching, gum chewing and jaw pain help build the picture.
- Symmetry.
One masseter is often larger than the other, which may affect the plan.
- Your goal.
Some people want a softer jawline; others want a more tapered V-line, which may involve more than one treatment.
What change to expect, and when
Masseter Botox reduces how strongly the muscle contracts. Over the following weeks, a less-used muscle may become less bulky, which is what creates the slimmer look. The timeline is gradual:
- Early days.
No visible change yet; mild tenderness or small bruises are possible.
- First couple of weeks.
The muscle feels weaker, and chewing tough food may be more tiring.
- Following weeks.
Visible slimming tends to develop as the muscle reduces in bulk.
- Months later.
The effect gradually fades as muscle activity returns.
Because the change is slow, many people do not notice it day to day. Photos taken on the treatment day give a fair comparison later.
Prices at Daybeau Clinic Seomyeon
At Daybeau Clinic Seomyeon, Jaw Botox 50 units is listed at 9,900 KRW. If fat under the chin or along the jaw is part of the concern, the ZERO steroid-free fat-dissolving injection 3cc is 15,000 KRW. These are first-visit prices in KRW, VAT excluded (10% VAT added at payment), checked October 2026, and first-visit prices apply once per new patient per item. Chin filler, if recommended, is quoted after an in-person consultation.
See the full price list, and read more on our jaw Botox page
and V-line contouring page.
Side effects and when to be cautious
Common, usually temporary effects of masseter Botox include tenderness, small bruises, mild swelling and chewing fatigue. Less commonly, people notice an uneven result or a change in how their smile looks, which a doctor can assess. Some people with very thin faces may find that slimming the jaw makes the cheeks look relatively hollower, which is worth discussing beforehand.
Tell your doctor if you are pregnant or breastfeeding, have a neuromuscular condition or take medication that affects nerves or bleeding. If you have jaw pain or grinding, a dental assessment is also worthwhile. Suitability and results vary, and the doctor decides at consultation.
Frequently asked questions
Will Botox make my whole face smaller?
No. It can make the lower face look narrower when a large masseter is the cause, but it does not change bone or the overall size of the face.
What if my face is round because of fat?
Masseter Botox will likely change little in that case. Your doctor may discuss other options, such as fat-dissolving injections for small localised areas.
Do I need repeat treatments?
The effect is temporary, so some people choose to repeat it once it fades. Your doctor will advise on timing rather than a fixed schedule.
Want to know whether your jaw width comes from muscle? Book a consultation
or message us on WhatsApp before your trip.
