Hamster Health Trouble?

Alright, my sister's hamster has his right cheek all bulging and red. When my mother inspected it, she developed the idea that there's something in there. Like a long tooth. The swollen cheek is not impeding the hamster's eating, but I imagine it will. Should I try to find someone who can take care of this, and if so, how? Does anyone know what it is, or how to treat it? If this were a human, or something else bigger, it would be so much easier. It has been present for a few days, the swelling seems to have gone down. It seems hard, like someting more than liquid causing the swelling. My mother does not want to take the hamster to a vet, as it may cost a lot of money to simply find out a simple thing. Suggestions?