How can I fight these impulse and obsessions??!!?

I have something called trichotillomania. It means I pull my hair excessively to relieve stress. I pull lots of hair and I am starting to get little bald spots. I'm worried because I don't want anyone to question me. My parents know that I pull my hair but they don't realize how serious it is. I do not have a therapist. But I can't stop pulling my hair!!! My hands automatically goes up to my hair to start pulling. I can't even remember how it all started!!! I'm only 12 yet the hair I pull is really a scary amount. I can't control myself. I want to be able to stop. But I've never introduced the idea of a therapist before to my parents. And most likely they will say no. There's a tip that if I keep my hands occupied I won't pull my hair. But my hands can't be busy all the time?!! So can I get therapy without my parents knowing?? Tips and suggestions would be very helpful. Thanks.