Help?

Sorry I really dont know where to post this. But me and my friends (16-17) were hanging at a park and some other person came over and started to talk to us. I didnt think anything of it, but he seemed to like cling onto me. He kept making sexual comments, picking me up and he groped me more than once. I really didnt know what to do so I just kept playing it off kind of ignoring it, my friends also did nothing about it and just told me how uncomfortable they were when he left for a minute. We usually hang out in that neighborhood and I'm worried to go back there. Am I overreacting? I may add I was wearing a little bit of revealing clothing.