There is absolutely no reason your teacher needed to do that. He is just a miserable jerk who likes to pick on students. THere are people out there who are ignorant, and refuse to understand, and I am sorry that this one had to be your teacher.

I arrived 30 min late for a final as well, there were whispers while I was walking in. I was just not into school. I failed that test. Another class (art history) she called me out while me and my group were presenting, said my answer was wrong, and got into an argument with me about external matters (in front of the whole class) this teacher, everyday, called on me "shy girl" and not my real name. Students just sat there looking in disbelief, but nobody said anything

This led to me transferring, changing everything, going home until I felt better.. things got so much better. there are people who understand and will help. But you need to let this go, things happen for a reason, you will just get stronger. You will look back and say this was just a bump on the road. He refuses to see your potential, but don't let that stop you.

This will pass.