I think you should talk to him, preferably in a public place, and basically ask him not to say bad things about you. But talk to him, not yell or get upset. It would be tempting to go off on him, but it will make you look psycho, not him.
If you decide to write a note, be careful in what you say just in case he does decide to show it off to everyone. Don't write anything that would come back to haunt you later, like a secret you two had, or deep feelings that you may be still feeling.
Finally, what may be the best choice is to ignore him, and get on with your life. Instead of walking up to him and embarrassing him in front of another girl, wait until you find a guy, and trust me, he will take notice. But don't just find another guy just to do this, take your time and find someone you truly care about.
Just remember that he wants you to react negatively and actually just react to whatever he does, so the best decision is not to give him what he wants. Play it off like you just don't care about him anymore, and you have your own life to live, because you really should move on to better things.
Oh, and don't beat the guy up. It would be funny, yes, but trust me, he won't stop bugging you after that. You will have to deal with him, and his mom, and whoever else wants to get involved.



