Well, a snake like a ball python, or a snake like a retic?

For a ball python, first just wait and see if it will let go after a few minutes. They really can't hurt you that bad. Sure, there will be some blood, but nothing even remotely dangerous.

I have heard a lot of people say dunking them under water works, but that would not be my first choice of action. Most ball pythons absolutely HATE to be sprayed with water, I know mine does, and so my plan if this ever happens is to sprits her with my misting bottle. I did this ONCE when she missed her mouse and bit the cloth "plate" I was feeding her on so she didn't eat substrate and started coiling around it. I was freaked out she would try to swallow it, so I sprayed her with water and she let go immediately. She then struck her real food like nothing happened. haha.

Just remember, after any bite, clean it up good with some peroxide and a little Neosporin. All animal bites and scratches CAN give you an infection, snakes are no exception, so it's silly not to do 90 seconds of simple first aid.