so ive recently been the target of these horrible girls who have spread a rumour about me which isnt true . how do i get everyone else to realise its only a rumour ?

ok, so last weekend i was at this party with my friend and her boyfriend when she went upstairs to the bedroom with him so i went upstairs to use the bathroom and her boyfriends really hot friend was standing and then he just kissed me and we went to the next door bedroom and done some things but at the end of the night we never had time to exchange numbers. i heard stories that he does things with loads of girls and hes a bit of a player but i really like him so i was wonderin if anyone has any tips on how to get him to like me back?