Technically, this condition is called dermatophagia and is often classified as an obsessive-compulsive disorder. There is a lot of very good therapy for this, and I would highly recommend seeing a cognitive-behavioral counselor for this. Therapists trained in CBT have a particular way of approaching these conditions that tend to work. Ask around to find someone trained — or use our Find Help button at the top of the page to find someone that may be near you in your country. Ask your parents for help in securing an appointment.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral