What should I do about this horrible situation that happened in school today?

Earlier this morning when I was in gym class and minding my own business dribbling and playing with a basketball a guy about 3 inches taller than be runs as fast as he can and forcefully grabs the basketball out of my hand. I said give me my ball, and he wouldn't give it to me. He said, I'm going to punch you" while he acted all tough and dribbled the ball. I asked him again for the ball, and he punched me extremely hard on my face on my mouth and my lips and nose. Then I punched him very lightly but missed to defend myself and it only ended up being the equivalence of a little slap across the face usually used to get someone's attention. Then he got angry so he very violently punched me across my left jaw and side burns and cheeks 3 times. My nose was bleeding by the time that happened, and I had blood gushing from my lip. My cheeks hurt like crazy, and my whole left side burn area was swollen and the nerves hurt there like crazy. I then called the teacher for help, and the teacher took me to the nurse. I had to go to the emergency room because I was hurt so bad. We're both 15 years old by the way. He hurt very badly. Is there anything I can do (not physically) so that he learns his lesson, like getting him suspended for many days or getting him in trouble with the police. As far as the police goes, if someone is up to the point of injury, THAT IS assault and battery and the person who gets attacked has the right to defend themselves if they are able to. Before I went in the health room, this guy didn't even want to admit what he did. He said, I didn't take the ball from him. I raised my voice so everybody could here and embarrassed person. I said, YES YOU DID TAKE THE BALL FROM ME, and you can't deny it. You're stupid and pathetic and a horrible person. "People like you end up in prison and aren't going to be successful in life." You're a disgrace to this school. He sort of frowned and he didn't say anything and looked guilty because KNEW he was wrong and he wasn't going to argue with an injured person. This person is dangerous and violent, and the police really need to know about this if this happens again, or even now. What are your opinions on this situation? I know I could have walked away, but he never actually said I'll punch you if you keep asking for the basketball. He just threatened to punch me right off the bat. By the time he punched me, I was too hurt to go to the teacher. He punched me so hard that I had to rest for about 10 minutes then walk very slowly to the health room. He could have caused fatal injuries to me. What do you think you would have done in this situation, and what would you do after the fact if this happened to you? Thanks.