There is a guy at my school, I sent him a follow request on Instagram, he accepted then one day later blocked me, should I send him a message asking him why he blocked me? We don't really know each other we are just in the same school.

If it is upsetting you that much, then ask him . Me? I would just block him back and forget about it-but if you would like to know then you will have to ask. Personally, I wouldn't ask, but my daughter... She would want to know and would ask. We really can't tell you what's best for you .