Side effects of treatment with botulinum toxin such as Botox ®, Azzalure (Dysport) include:
- needle site redness
- bruising or hematoma
- if injected above the outer half of eyebrows, can cause the eyebrows to be heavy.
- if injected too close to the upper eyelid or rubbed inadvertently causing migrate into the eyelid muscle, it can cause a droopy eyelid.
There are reports of side effects caused by distant migration of botulinum toxin, including weakness of swallowing. However, the current understanding is that when the total amount of toxin used is kept to the minimum required for effect, used after prudent medical consultation and understanding of the depth of injection and muscles being treated, Botox is a safe treatment in the right hands.
