<human>: Can you give me the gist of the text in a nutshell?

So I dated this girl last year, lets call her Becca. Becca seemed nice enough, we had fun together, but nothing ever happened past making out, which I was fine with. During summer break, I decided to break things off because I realized I wasn't having very much fun around her and if I wasn't enjoying spending time with her I shouldn't probably date her. After breaking up, we agreed to try to be on good terms, but it was still awkward seeing each other at school and such. Little did I know, directly after breaking up with her she started spreading lies about me. According to her, I forced her to give me a blowjob in a movie theater, and I lost a lot of friends to that. I didn't even find out until around 7 months after breaking up with her. I realize now that she's an absolute attention whore, and maybe a bit crazy. Now one of my best friends is enamored with her, like head over heels and I feel like it's too late to help the poor guy. I want to tell him that she's insane but I'm afraid of the backlash I may get and that I might lose him as a friend to her. What should I do, Reddit?
<bot>: Broke up with girl, she spread bad lies about me throughout school. Friend head over heels for her now and I  fear it is too late to help him.