I think teachers have kids they like and kids they don't. I was one of the kids my teacher didn't like in 1st grade. We were having teacher-reads-a-book hour and while she was reading a bee came in and stung me on the face. I raised my hand for 7 minutes (I watched the clock because I just learned how to do it) to go to the nurse's office. She finally was sick of me raising my hand, so with the most disgusted voice said, "WHAT, SHICCY?!" When I told her what happened she made somebody actually escort me to the office and apologized.
Same teacher gave me daily detention because I would play with the kids in line for the school bus. I walked home >1mi, but it was like having another recess, so it was a lot of fun. Some kids missed the bus a few days because they were too busy playing. Instead of punishing the kids that missed their bus, she punished ME with detention becasue she didn't like me. I told my mom about the bee incident, but she had to ask me about the bus incident. She had enough of this bitch and went in, had words, and her response was essentially, "I'll do what I want". That didn't go over well with my mom. Luckily she's a friend / knew the principal well becuase of my older sisters. I was a good kid for the most part, so she literally took this teacher by her arm and escorted her to the principals office like she was a child and had words there as well. The principal agreed the teacher was ridiculous and a bitch and told her to knock her shit off.
I had no issues thereafter, however had I not had my mom to do this for me, I cannot imagine enduring the rest of the school year with this cunt.
This teacher was also my 4th grade teacher's best friend. She treated me like shit, too, but knew better than treat me much different than the other kids because I had someone to advocate for me.
The TL;DR- I'm sorry your teacher was a cunt and you didn't have somebody to advocate for you on your behalf :(