WOW you have more guts then I had when I was a teen. and Im glad you were able to do this and I hope it doesn't back fire on you. but just in case you might want to have a plan in place for yourself by the time you meet with the coach, see now there are nation wide mandated reporting laws that say teachers HAVE to report and suspicions of anyone being a danger to themself or others especially since the school shootings and so on begain and laws for abuse prevention were put into place.

If you did not show your coach any fresh cuts and he has not seen any fresh cuts if it starts to backfire on you , you might be able to get away with saying you were checking out his response for a friend.

But being mandated reporter he is legally bound to tell your parents and or the school psychologist and require you to see the school psychologist and or for possible referal to a mental health agency outside the school.

So you might want to before you meet with the coach research your community now for possible therapy and crisis services. that way at this meeting if he tells you he had checked on the school policys and laws and found out he had to notify your parents and th e school of your problem and you have to see the school psychologist and or other therapy avenues you can tell him you have it covered you will be meeting with a therapy professional and be discussing disclosing to your parents with that professional.

you can find services that help with self injury behavior by looking in the phone book under - mental health services, community services, crisis hotlines, Rape crisis centers and agencies, psychiatrists, psychologists,

Good luck to you and I so hope this doesn't back fire on you.