Lump on gums or mouth?

Hello! I noticed my 12 year old cat had a lump in her mouth today. It is right on the left side, right in the middle near the corner.

It doesn't seem to be any strange color. She has had a number of teeth removed over the years, but nothing anytime soon. You can see them lump under her skin by just looking at her face.

It doesn't seem to be bothering her, even when I pull up her lips to examine it. I set an appointment for the vet tomorrow, but I was wondering if anyone might have an idea of what is going on. Thanks.

Without seeing it in person, I'd hazzard a guess and say it is possibly an abcess.
But you say it doesn't seem to be bothering her and abcesses are generally painful.

Yeah it doesn't seem to be painful. My girlfriend said she was just able to touch it, and she didn't seem to be bothered. Not that I think it has anything to do with it, but my cat has diabetes and inflamitory bowel disease.