Can Botox in the masseter cause blurry vision?

This sounds very unlikely but you should have it checked out regardless. Please return to your injector for a followup.

I am not aware of that form of complication after Botox of the TMJ region, however I recommend that you see an  immediately to evaluate your situation. Be sure to tell the ophthalmologist about your Botox treatment.

In medicine, nothing is impossible, regardless how improbable. I can't imagine how this would have happened if given properly but if you are getting blurry vision is its critical you see your physician, go to a ophthomologist and been seen by an emerge physician. James P. Bonaparte, MD, MSc, FRCSCHead and Neck Surgerypracticing in Facial Plastic and Reconstructive SurgeryAssistant Professor, University of OttawaOttawa, Ontario, Canada

I have never
seen this issue arise and can’t think of a mechanism for that to occur. I’d go see your eye
doctor….