Mouse with puffy cheek?

One of my breeder females has a lump around her cheek. It looks like her left cheek is completely swollen. What can be causing this? Is this most likely a tumor or some type of cancer? Or something else?

Likely a tumor, one of mine had a huge tumor on her face, it was crazy how fast it popped up, I feed them off when that happens.

So feeding off a mouse with a tumor wont harm my snake at all? Also, what if it is an RI or some other illness? Whatever it is, it wont harm my snake regardless? I don't want to take a chance of it being something else.

Feeder.