The only time I remember being hurt by the words of a classmate was in 5th grade, when a girl told it would have been better off if I were dead.
I was upset, but after I while I thought that her opinion wasn't as important as mine, and I didn't think it was better if I were dead so f*** her.
However I got my revenge.
I poured orange juice on her t-shirt in the lunch room the same day. She asked me why and I told her the reason, she said "I'm sorry I was joking" but I didn't forgive her.
And then I became passive-aggressive towards her and I started criticizing everything she did and said.