My cousin groped me..

We were at a thanks giving dinner and I went in the kitchen to get the rest of the food and I needed help.i was going to ask my sister to help me but my cousin volunteered.bringing out the last bit of food he grabs my hand a pushed me against the fridge lifting up my leg and and I was pushing him away .for about 2 mind this continued and then he stopped he looked at me fixed his are and left

What should I do??..