Hi There. I Have Had Surgery To Remove Bilateral Cysts

Hi there. I have had surgery to remove bilateral cysts on my neck. The surgeon says that he might have damaged a nerve that runs along the jaw because when i smile, the bottom right part of my lip doesn't descend and looks distorted. I can't find much information about this issue. How do i know if the never was simply bruised or permanently cut? and what are the treatment options. He said that it could take weeks or months to recover.

Many thanks