Best man felt me up before wedding

I was 22, it was the night before my wedding and I did what usually brides do and spend the night away from my to be husband at his sisters house We all crashed in the living room and as I'm falling asleep on the couch I feel fingers feeling around on the cushion. Then I feel fingers on my skin. I shoved the hand away thinking someone is just flailing in their sleep. Then a man's hand grabs by left breasts and squeezes, I hear a chuckle, then snoring. I laid there in shock for the rest of the night too scared to move This was 20 years ago but I still think about it. I never told a soul.