Hi,
I have just joined as I stumbled on your problem and thought I may be able to help. Firstly I take it your son is at secondry school. I have stated this as during eenage years a problem can be thrown out of proportion. When my son came home from school complaining of being bullied I spoke to other parents to see if this was the case. Unfortunatly it was. It may be worth speaking to other children from the school to establish if this has been ongoing. If your son has been hit by a teacher I will be very suprised if its the first time he/she has done it and also if there has not been a problem with your son. If you are completly sure this has happened as told by your son I would advise going straight to the school governers. I say this becaue teachers stick togther, and the head teacher will avoid bad press. If you write to the governers they have to act on it and interview all parties. If no joy from them, then go straight to your council educational authorities and ofsted. Hope this helps and that things work out for you. Good luck.