boys, prom, and blowjobs

I've been seeing this guy Peter lately and we were going to go to prom together. I recently lost my virginity to him. Last weekend I was at a party and people were talking shit about him, so I stood up for him. They al laughed and said Peter had told all his friends how bad I was at giving blowjobs and that I use too much teeth. I was so embarrassed. I ran off crying. I'm really hurt because if there was a problem it should've been addressed between us and no one else. I really don't want to be with him but prom is in 3 weeks and we are already in a prom house together. (A prom house is a house seniors rent out for the weekend of prom). What should I do?