Talk to the Principal and get some suggestions. Also, talk with your parent(s) or guardian(s) as soon as possible. I used to take on bullies in school, and this can lead to problems. Once, I got in trouble for it. It can get you get kicked out of school. So, I would highly suggest you go through the proper channels to deal with this person.
beat him up usually when you tell a teacher it just feels embarrassing and it does get worse cuz then the kid gets in trouble and another kid will be mad that kid gets in trouble. Or you make a witty come back.
Tell the principle. If this doesn't work, talk to the cops about it. DO NOT just accept it. And try not to get in a fight unless he starts it. Feel free to stand up for yourself in the situation that he hits you and tries to beat you up, he may not bully you anymore if you stand up to him. Bullies want someone easy to pick on, not someone who will fight back. also, just a side note, don't go straight for the balls, this can be a mistake because it's too predictable and to easy to defend against. only go for the balls if they're EXTREMELY vulnerable, I've been in two fights with bullies at school, both times I went for nut shots, and both times I failed. once he caught my leg and about took me down to the ground, the other time he nailed me in the jaw. just be careful in a fight because this kid could have experience.