Any vets or educated cat people?

[MisterKyte]

I've seen tumours before... doesn't really look like that to me and since he's an outdoors cat, I would think that it's an infected injury like people have already been suggesting. Is there any puss (white, yellow, green)? If there's puss, than I'd definitely say it's infected.

This is why my cat is an indoors only... well, that and the fact that she's too chicken to go outside anyways but I hope this turns out to be minor, good luck!