Brooks Kingsnake strange digestion and behavior? (diarrhea and biting himself)

[Gocntry]

I am scared that I wouldn't know what I'd be doing. What if it turns out he doesn't have parasites and im giving him medicine he doesn't need? I am looking at all the options right now, but if I end up killing him from messing up, I wouldn't be able to bear it.

Totally understand that, having a living critters life in your hands is a big responsibility, If one of my snakes died under my care That would be a crushing blow.