Uneven smile after treating masseters with Dysport.

Thank you for posting your question. While the Dysport injection targeted the masseter muscles, it is possible that the toxin migrated to adjacent muscles involved in smiling, resulting in a temporary change in your smile. The effects of a neuromodulator typically last 3 to 4 months, and therefore your smile should return to baseline in a few months. 

Sorry to hear about your experience. It is possible that Dysport diffused to the adjacent muscles and did not stay confined to the masseter muscles resulting in a smile abnormality. Your smile will return to normal once the Dysport has worn off.