the second the thought above.Honesty, the headmaster's credibility and position will be taken into consideration.My advice is not to go head on against him.he is prolly doing his job,and is damn severe with it.So whether you are wrong or not, (which you are not)just bear with him and make sure on dont get in his blacklist.
i second those thoughts.Martial Arts are great help to keep us zen and calm.the best one for me, ill say bone art martial"Aikido" the most lethal of all.xD