What's wrong with him?

[SawCookie]

My California 50/50 King Snake recently developed a small brownish spot on his underside that looks like it's shriveled up and dead, what could be wrong with him? I tried to post a picture but i cannot figure out how to post it on here, the attachment thing doesn't work. I really need to figure out what is wrong with him so I can help him, I don't want him to be in pain. Please let me know so he can stop being in pain! The only thing I can think of is skin rot, but I don't know what that looks like or how to cure it. I can text or email pictures if that would help diagnosis, please let me know!