Suggest Treatment For Self-injurious Behavior In A Child

my daughter of 13 years old she is cutting her self sence she was 11 and she hasent stop and i verly notece this year and i dont know how to stop her doing it she is addicted she cant stop doing it how i can help her she says that she has it under control and when i talk to her about what can happen she just walk away like if i wasent there how can i help her do you know