At the site of the injection
- Pain - mild.
- Swelling - mild, resolves usually within a few hours.
- Redness - may last for 1-2 hours.
- Headache.
Systemic (uncommon)
- Nausea, fatigue, and other flu-like symptoms.
Duration of result
3-4 months depending on the dosage, the concentration, the injection technique and the size of the injected muscle.
After repeated doses the duration of muscle relaxation is prolonged, occasionally up to 5 or 6 months
Note that where deep lines exist, often the frown lines, more than one treatment may be required due to 'skin-fold memory'. Cessation of muscular activity for 6 months will usually result in a dramatic reduction in the depth of these lines. Complete effacement of very pronounced lines may not be possible without fillers.
Complications
Bruising is the most common complication. This is more common in certain treatment areas e.g. crows feet, and in patients who bruise easily. Patients should avoid medications that thin the blood such as aspirin and non-steroidal anti-inflammatories for 2 weeks prior to injection.
Eyelid ptosis (drooping of the upper eyelid) - this uncommon complication usually lasts only a few weeks. During this period eye-drops can be administered to temporarily elevate the eyelid until the muscle recovers.