Can masseter Botox do permanent damage to the nerves or muscles? (Photos)

Hey there
Masseter injections do carry the risk of botox migrating anteriorly, this would affect the risorious muscle which is responsible for the lateral pull of your smile. It's much more likely that the botox has temporarily paralysed this muscle rather than you having any permanent nerve damage. Hopefully it should be wearing off some time soon.

It is possible that the risorius muscle was affected by the injection. If the injection is too anterior, this can happen. It should all get better as Botox wears out. It doesn't cause permanent weakness. Dosing in this area is high, so it might take longer than normal to resolve.