I just cut myself. I feel bad because I broke all sorts of promises doing so. I'm seeing a psychiatrist and a therapist, I'm not sure if I should tell them because they might send me to the psych ward where I belong but don't want to go anywhere near, because I'm going to college. I just wanted to tell someone a secret.
I don't know if perfect record is expected of you, but honesty is therapeutic. Chances are, if you already have one secret, you'll be likely to add another, and then 'might send' gets closer to 'will send'. I have no experiences in this field though.
If you make it clear you dont self harm as a suicide attempt, they can't involuntarily admit you. Self harm in itself isn't legally a reason to do so, and they always assess this before admitting someone. So feel free to tell them, just be careful to make it obvious you didnt try to take your own life.
If you promised people you wouldnt and you did, you should tell them. Fuck them if they get mad at you. I lost my best friend because I told her I self harmed and she was angry about it. Its a time to support them, not get mad at them.