I think your tortoise needs attention from a good exotics vet to clean up and trim the area to make sure whatever caused the problem is eliminated. IE, infection, poor bite causing overgrowth of beak, or some other cause.This is what the upper jaw looks like now View attachment 381247
I did more cleaning and applied some medicine . This is the final look .That hook-like part needs to be taken off before it catches on something and causes a bigger problem. If you don't think YOU are able to file it off, then take the tortoise to a qualified exotic tortoise vet. The actual missing part isn't a problem. He probably doesn't feel anything.
