Teachers?? Answer please? i need to know where i stand in this situation?

i changed my name on facebook to a teachers and picture then added teachers. stupid ino im sorry and feel awful and it was really stupid. but i spoke to my head of year he said keep it quiet and just removeit. but now the head knows and wants too kick me out of joining 6th form in spetember next year :/ my mum said its fair game his fb settings should of been private but it was silly of me. she wrote an email and he just ignored all her points and said if your are unable to attend the meeting my sixth form application will be withdrawn.. however she works full time and has a very demanding job so this may be a problem. my mum knows someone who works in welfare education and shes speaking to her, who also hates the head. i just wanted to generate some rights and helpful pointers if thats atall possible. thankyou!