What is the most commonly performed procedure in dermatology?

 

As the title suggests, it’s Botox.

 

Because the number of procedures is so high, side effects are inevitably more common as well.

 

"You know, that kind of thing just happens sometimes."
"Everyone’s muscle structure is a little different."
"The product just spread a bit."

 

Have you ever received an explanation like one of these?

 

So, why do side effects occur?

And more importantly, what should you know to prevent them?

 

This is information that not only doctors, but also patients should understand.

 

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Botox Side Effects: Cases and Causes

 

(1) Forehead / Glabella (between the brows)

 

• Samurai Brows (asymmetrical eyebrows)

 

Reference:
Complications of Botulinum Toxin A: An Update Review, George Kroumpouzos, MD (2021)

 

Cause:
This side effect occurs when injections are placed only in the center of the forehead or when the patient has strong forehead muscles and the dosage is insufficient.

 

Treatment:
It can be easily corrected by injecting an additional 2–4 units (U) above the area where the outer eyebrow has lifted.

 

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• Eyelid Ptosis (Drooping Eyelid)

Example of eyelid ptosis after Botox (Image source: Google)

Cause:
For individuals who habitually use their forehead muscles to open their eyes, weakening those muscles through Botox in the forehead or glabella can make it more difficult to keep the eyes open.

 

Additionally, if the injector places the injection too close to the eyelid or inserts the needle too deeply, the toxin may travel along the periosteum (the membrane covering the bone), leading to eyelid ptosis.

 

Complications of Botulinum toxin A: An update review, George Kroumpouzos MD(2021)

 

Treatment:
If this side effect occurs, there is no specific remedy — you simply have to wait for the effect to wear off over 2–3 months.

That’s why prevention is absolutely critical.

 

Using a higher concentration of Botox, having the practitioner manually block the lower eyelid area during injection, and massaging upward firmly can help prevent the toxin from spreading downward and reduce the risk of this complication.

 

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(2) Masseter (Jawline) Botox Side Effects

 

• Asymmetrical Mouth Corners

Example of Asymmetrical Mouth Corners
(Image source: Google)

Cause:
This occurs when the injection is placed too far forward, or if the treated area is rubbed afterward, causing the toxin to spread toward the front and affect the muscles around the mouth — particularly the risorius muscle.

 

Treatment:
Just like with eyelid ptosis, once this side effect occurs, there is no direct treatment — you simply have to wait for the effect to wear off, which takes about 2–3 months.

 

Prevention is key.
Based on my experience, I recommend palpating (feeling) the masseter muscle before the procedure to define the injection area, then injecting across 3 to 4 points.

 

In addition, press the front of the jaw during injection to prevent the toxin from spreading forward.

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• Cheek Hollowing

 

Cause:
The masseter muscle extends from the jawbone to the cheekbone. If the injection is placed too high or too far forward, it may not only reduce the masseter but also affect the cheek muscles, leading to cheek hollowing.

Treatment:
Typically, it resolves naturally within about three months, but there is virtually no immediate remedy.

 

If quick correction is needed, the only option is injecting a hyaluronic acid filler into the cheeks.

 

(For those with important events like weddings or photo shoots, it is advisable to avoid dermatological procedures at least one month in advance.)

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Tadpole Cheeks (Candy Ball Effect)

Reference:
The Anatomical Basis of Paradoxical Masseteric Bulging after Botulinum Neurotoxin Type A Injection

 

Cause:
When Botox is injected only into the deep layer of the masseter muscle, the superficial masseter remains active and becomes more pronounced, leading to a bulging appearance in the cheeks—commonly referred to as the “candy ball” or “tadpole cheeks” effect.

 

Treatment:
Injecting a small amount of Botox into the superficial masseter muscle can generally correct this issue easily.

 

Prevention:
To avoid this, the injector should ensure that the medication is not delivered exclusively to the deep layer. Using a technique where the needle is slightly withdrawn during injection can help distribute the toxin into the superficial layer as well.

 

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(3) Botox Around the Mouth and Lips

 

• Mouth Area Paralysis

Reference:
A successful management of severe gummy smile using gingivectomy and botulinum toxin injection: A case report, Diana Mostafa

 

Cause:
When Botox is injected around the lips to treat a gummy smile, using too high a dose can result in the upper lip not lifting when smiling.

 

Treatment:
In some cases of asymmetry, an additional injection may be applied to the opposite side to balance it. However, if paralysis has already occurred, there is no effective treatment and one must wait for 2–3 months until the effects wear off.

 

(Note: Paralysis around the mouth and lips can significantly interfere with daily life, so extreme care is required during injection.)

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How to Prevent Botox Side Effects

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1. Extend the Interval Between Treatments

Short intervals between injections increase the risk of developing resistance (antibodies), and excessive muscle atrophy may lead to compensatory muscle overgrowth, producing unwanted effects.

 

For wrinkles (forehead, glabella, eye area): Minimum interval of 2–3 months

For jaw, trapezius, calves, and other body areas: Minimum of 4 months

(Some clinics may recommend reinjection every 1–2 months for profit, but this increases health risks for patients.)

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2. Avoid Excessive Dosage

 

Overdosing can increase the risk of resistance and cause excessive muscle atrophy.

Recommended Dosage:

• Jaw Botox: 50–100 units (U)

• Body areas: 100–200 units

 

Do not exceed a total of 300 units per day.

(For details on Botox types, please refer to a separate article.)

 

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3-Sentence Summary

• While individual differences exist in muscle size and position, most Botox side effects stem from inadequate technique by the injector.

• Since each injection site can cause different side effects, a solid anatomical understanding is essential.

• Side effects are rarely permanent and the procedure is generally safe, but it requires caution as patients may suffer discomfort for several months.

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That concludes our information on Botox side effects.

 

We hope this article has been helpful to many of you.

 

If you have any questions about the procedure, feel free to leave a like or comment—we’ll respond kindly and thoroughly.

 

Thank you!

 

📍 Primi Clinic
3F, 52 Seongsuil-ro, Seongdong-gu, Seoul (Primi Clinic)

 

📍 Primi Clinic
서울특별시 성동구 성수일로 52 3F (Primi Clinic)