Do I have an ulcer?

I think I have an ulcer in my mouth. I say think, because I have no idea what one looks or feels like, having never had one before. At first I thought it was just a cut or something, but it's taken so long in healing that maybe it's not.

It's in the front bottom part of my mouth, on the lip side down where the flesh meets the gums. Small, slightly hard, white, and painful, since it keeps rubbing on my gums and teeth :(

Anyway, if any of you people know for sure if it is or isn't an ulcer, then I can either just treat it with hippie stuff or ignore it. No, I'm not going to a doctor about it *shudders*.