What are the common side effects of Botox and HA filler injections around the mouth (DAO area)?
⚠️ Seek urgent care if you notice these warning signs
Contact your injector immediately or go to an emergency room if you experience: sudden skin color changes (white, blue, or purple skin) near the injection site, severe or worsening pain, vision changes or loss, rapidly spreading swelling, signs of infection (increasing redness, warmth, pus, or fever). These can signal a vascular complication or serious infection requiring immediate treatment.
Short answer
Most side effects from Botox and HA filler injections are mild and short-lived, including redness, swelling, and bruising at the injection site. Serious complications are rare but can occur, so knowing the warning signs is important for your safety.
What the research shows: HA filler side effects
Studies consistently find that the most common reactions after HA filler injection are injection-site reactions such as redness (erythema), swelling (edema), and bruising. These typically resolve on their own within days to a few weeks [1]. Around the mouth specifically, the same pattern holds: swelling, bruising, and minor contour irregularities (small lumps or unevenness) are the most frequently reported issues [5]. For marionette lines near the DAO (depressor anguli oris) muscle, filler placed in the deeper fat layers carries similar risks [6].
Less common but more serious filler complications include: persistent or late swelling, skin discoloration, nodules or granulomas (firm lumps under the skin), infection, and biofilm formation. The most serious risk is vascular compromise, meaning filler accidentally enters or compresses a blood vessel, which can threaten tissue or, in rare cases near the eye area, vision [2] [3]. These severe events are uncommon but require prompt treatment, often with an enzyme called hyaluronidase that dissolves HA filler [3].
What the research shows: Botox (botulinum toxin) side effects
Botulinum toxin type A injections, including those targeting the DAO muscle to lift the corners of the mouth, have a strong overall safety record [8]. Common side effects are also injection-related: temporary bruising, mild swelling, and tenderness at the injection site. Because the DAO is close to muscles that control the lip and smile, temporary asymmetry or unintended muscle weakness in nearby areas (such as difficulty smiling evenly or slight lip drooping) is a known risk if dosing or placement is not precise [8]. These effects wear off as the toxin naturally fades, typically within 3 to 4 months. The consensus guidance emphasizes using lower doses and careful muscle analysis to reduce these risks [8].
What this means for you
For most patients, side effects from both Botox and HA filler in the perioral (around-the-mouth) area are temporary and manageable. Choosing a well-trained injector with a thorough understanding of facial anatomy significantly lowers your risk [5] [8]. Persistent swelling, unusual pain, skin color changes, or any lumps that do not resolve within a few weeks should be reported to your provider promptly [1] [3]. Before your procedure, make sure to discuss your full medical history, medications, and any previous reactions to injectables.
What to ask your surgeon or injector
- What specific side effects are most likely for the DAO area, and how long should I expect them to last?
- Do you have hyaluronidase available in the office in case of a vascular emergency?
- What signs should prompt me to call you or go to an emergency room?
- How will you tailor the Botox dose to avoid affecting my smile muscles?