Dear happycheeks

HUGS!
You seem like a sweet girl and you mom is acting harsh and cruel. Unfortunately you are programmed to listen more to her than to us, even if you don't want to. If you have a therapist she may help you override the "mommy voice". I am not saying your mom means to hurt you, she is probably doing what she think is best, but what she's doing to you is bad.
I have never cut myself, but I understand the impulse when anger and frustration well up and there is no valid way to express them, hurting self seems the only way to interrupt the charge. The pain stops the anger, and turns you toward nurturing yourself. Or at least "usually" it does turn like that. Does not mean that this is you.
It seems to me your cutting, may be partly a response to your mom's judgments. You just shown us how she is trying to SHAME you, rather than have compassion, and try to understand why possibly her daughter may be doing something so horrible to herself. It can create a vicious circle. She shames you, you react the only way that seems to bring relief, but that only brings more shaming. Please do not hate yourself for this.
This is a version of a mental exercise I had found helpful for myself:
(Imagine yourself years older, working as a child psychologist and someone hauls in a crying little you, however old you were when you just started cutting herself, or maybe some other form of self hurting. You look at her and your heart goes out to her, and you wonder why this beautiful innocent child feels so awful about herself, and how to help her. Let yourself sit with those feelings, just watching the young you through the eyes of the adult you. Love her.)