Please help.

Hi, I'm Rachel and I'm fifteen years old. I've always known I've had issues, but I just thought they were bad habits. I stumbled upon this website, and now I'm beginning to get really scared. Since I was little I sucked my thumb, and this went on until I was almost eight years old. Once I stopped that habit, I began eating the skin on my fingers, usually around the nail. I chew them until the bleed, I digest the skin, and I lick the blood. I do this on my thighs, too. I don't know what these little black dots are on the skin on my thighs (I think they might be little in grown hairs), but I squeeze them until stuff comes out and they bleed. I eat the substance and then when scabs are made, I peel them off and eat them. I can sit in the bathroom for hours doing this. I also do this with my acne. I eat the puss and liquid, and the scary part is that I can't stop! It's absolutely disgusting, but if I pop a zit and don't eat or rip the scab off, it will drive me insane. When I get nervous or scared or I play sports, I use my thumbs and other fingers to peel the skin off around my nails. It's getting so bad and I'm so self-conscious about all of it, but I just can't stop. My fingers are always sore, I can't wear nail polish, and as a teenage girl, I love nail polish. I've tried putting this type of polish on that tastes bitter and is supposed to deter me from doing it, but I just can't! I get used to the taste of the bitter and keep going. It's been years now and I don't know what else to do. My friends comment on it, my parents comment on it, and I just feel like such a disgusting human being. Please help me?