How do I help a hurt chipmunk?

Well,unfortunately, the obvious one is the vet, which is what he really needs... You could always just bug your parents until they'll let you take 'im. But that's not a guaranteed way of getting him the help he needs. If you had any money and were serious about it you could take him yourself but I get the feeling that you don't have the money to take him yourself. Honestly though the best thing for him is the vet... vet > internet.