harassed at a work party

So, its been a year for me experienced this so i have to attend party at a 5 stars hotel with my boss due to my interships program and i have to wear dress so i choose black short dress with long sleeves and heels. Everything went fine at the party. Until one of my boss best customer( he’s american) male prob around 40 approached me and said hi. He also shocked when i told them im 17( im 18 now) he said he once ask want to take me to his room and of course i was shock but keep it professional but then he grabbed my shoulder and down to my spine but before he touched my butt, i stopped him then he giggles and touch my face. I was so shocked. He said that im beautiful and etc but i then ran away and try to avoid him. I feel scared cause thats the worst harrasment ive got. I usually get cat called but im chill but this one i was speechless and it came from “Class A people”