I can't get it off :/ I have been holding the back between my teeth, and gripping it hard enough that there are dents in my fingers but no matter how much I twist it will NOT come off. It was put on with pliers, and I don't have any. I'm afraid to try anything else because sometimes it hurts the actual piercing...

I would go back to where you got it pierced. They'll likely have the tools and the know how to get it off.