honestly... depends of where it is and what the situation presents itself as...
If it's in the internet, you got all rights to silence or block the person or ignore it or absent till they stop...
if it's more irl... that's going to be complicated...
for context, the situation isnt THAT bad, its just that a guy rlly gives me the creeps, he had admitted to me that he would secretly take pictures of his cousin and everytime we are in class he goes and takes a look at me atleast once (4 more context, i sit near a wall w literally no posters so there isnt rlly any reasons he should turn around anyway---)