this is a stray cat I feed. He's reecntly been licking this area for a bit. It appears unhealthy. Do you think it's something that will heal on its own? Or is there something I can do besides taking him to the vet?
That could be anything from a bite developing an infection (incipient abcess) to a tumor starting, and without vet care, there's no way to know for sure. IF there is no way that you can get him to a vet, and since you can handle him, I would suggest googling local rescues to see if someone can pick him up and get him the help that he needs.