OK my ex-boyfriend is a realllllllllllllllll pain in the butt sooo he tells his friends that he went out with me for a bet which he didn't and during school he calls me a dusbag and I don't like it because a guy I like now is wondering if I am and the dance is coming up so oooooooooo what should I do? To make him stoppppp

I wouldn't worry too much about it. People will say mean things, whether they're justified or not. Just be who you are and let people see by your actions what you really are like. That will overcome whatever people who don't know any better may have to say.

I would recommend not showing that it bothers you. Don't debate it with people if someone says oh I heard such and such about you just laugh and say oh yeah did you also hear I'm a secret spy who is really a robot or something as equally laughable. If you take the higher ground and he see that you could care less what he says he will stop. Anyone who believes stupid gossip from a stupid boy is well, stupid.