Do surgery? This is an opening in the mouth.
It hurts, okay? Can't eat hard food for a long time, can only eat liquid food?
A place? Said it was worn off? Actually, it was cut off ...?
Not that piece? That protuberance is called mastoid ... on the mandible? The one that moves up and down ...
Figure? Is it in the book at hand? ..... to help you find it ~