Boyfriends friend said I groped his crotch when I was drunk! I don't remember this! :(?

I got REALLY drunk on my birthday on Saturday. I hadn't eaten dinner and rarely drink. My boyfriend bought me a few shots and next thing I know I'm home... in bed in the morning. I am mortified. I guess I was so drunk I vomited. Total light-weight. I know, I know... shouldn't drink. I rarely do and guess I just haven't learned my limits. I was talking on the phone with my boyfriend tonight who said that his buddy told him that I "groped his crotch" and made him feel very uncomfortable. I do not remember this AT ALL. I suspect he's making it up, but I don't know. Doesn't seem like something I would do. I told him I don't think I did that, am mortified and blacked out (never have before except once when I was 18 years ago when with girlfriends drinking for one of the first times)... not sure how to handle this! Now I'm afraid to show my face around his friend! How would you handle this?