My cat is going to the vet today, because she has a spring from a pen lodged on the roof of her mouth. It has caused all of her teeth to turn yellow on that side, as well as create a hole on the inside of her lip. I'm afraid she has a blood infection. What are the signs of that for a cat?
I hope she is alright, I take it that you didn't catch the injury right after it happened? Holes are generally bad, becuase they are a sign of open absesses, or gangrene. Gangrene in the head is a Very Bad Thing. Let us know how the vet visit goes. If you're not there now, you're risking your cat's life.
Never trust a tall dwarf... he's lying about something.