So I don't see this guy getting out of my life any time soon. I already reported him to the teacher, but apparently whatever she did didn't work. What do you suggest I do?
Of course whatever she did didn't work! I know from experience teachers do squat when it comes to a bully or someone who wants to fight you. Usually people who want to fight you, especially for that particular reason, aren't motivated by any logic at all and entirely by their own machismo. It sounds like either he'll get bored of trying to beat you up or you'll end up fighting with him. If worse comes to worse and he fights you, put up both your fists in front of your face, making your forearms into an upside down V while anticipating any blows like this:
These are just my theories I've been going over my head for a while and I've never put these theories into practice in my entire life so take what I say with a big ol' spoon of salt. This arm and fist positioning with your arms will help deflect any blows he might throw. If he tries to punch straight through, you can snap together your forearms to form a sort of shield. Sounds like he's just a thug wanna be so chances are he'll do a wide swing, like a sideways pendulum. If he's swinging wide with his right arm straight, you can block it with your left forearm, putting your forearm to the side to cushion the force before his fist could get close. If his fist were to make any contact, theoretically a great amount of force would have already been dissipated against your forearm.
If you absolutely, positively must throw a punch, wait until you block one of his punches. Remember to use your knuckles when you strike and I mean where your finger actually connects with the hand, not the little joins in the finger or you may end up breaking your fingers. If it's a wide swing, he'll leave himself completely open. You can use that opening to strike a number of sensitive areas. The 'false rib' or the 'floating rib' areas are tender places where there's thin, un-callused skin over hard bone. The clavicle (bone at the base of your neck running to your shoulders) is also a good sensitive place on the body. See for yourself by tapping your clavicle a few times with your knuckles. Don't aim for the face because there's all sorts of sharp stuff there like teeth, cheek bones, eye sockets that could cut your hand up bad.
The most important rule is to never let yourself get thrown to the ground or trip up because while you're standing up, you only have to be afraid of his fists. If you're on the ground, now you gotta deal with his whole body weight. If you trip up, get back up as quickly as possible.
THESE ARE ALL THEORIES and I do not recommend in the slightest bit you do anything beyond the part where you strike back. This guy sounds like a thug in training so he could very well gather more of his friends to come at you a second time. Use these theories ONLY as an ultimate last resort after calling the cops.