God forbid an honest mistake?

He's not worth another second of your attention. As you said you try to avoid him, thats a good start. If you're in his presense and he's not asking you a direct question don't look at him or talk to him. If he yells at you in the hallways pretend you don't hear him and keep walking. Have as little to do with him as you can. If there are things you like to do in school that invove this man give them up. If after all this he wants to know why you're not invoving yourself in any activities that he's part of, tell him the truth. Something to the effect of "I'm not taking part in anything you're involved in"(spoken very politely). Then turn and walk away. Again always say whatever you have to say to him oh so very politely. All the other times you see him don't make eye contact and definitely don't talk to him.