My classmates laughed at me in public, completely ignoring my feelings. It's really hard ...

If you don't care and stop showing your feelings on your face, then this classmate will feel boring after mentioning it for 2 or 3 times, and it is unlikely to change his skin color in a short time, so change his attitude. When he says you are black, face him with a cold tone and expression. I think he can understand your anger. If it really doesn't work, then refute, that boy can't have any shortcomings, right? And black is right. Isn't Obama still the president?