Scared! Please help.

Just yesterday, I was picking at a scab on my knee. I picked at it until all the scabs were gone, and my knee started bleeding. In the process, I grabbed a tissue to stop the bleeding but I continued to pick at it until all my scabs were removed, and the skin underneath was pink. And then I was suddenly overwhelmed with this fear that there was something wrong with me. I realized that I liked picking at scabs and I feel joy in doing such things. So I went online and typed the question: am I normal? I came across this page and I realized that there were many people out there like me. I read many posts and soon realized that I had this problem of picking at my skin, scalp, and nails since maybe I was 12. It's crazy that this skin-picking problem never occurred to me. As I read the post, I started remembering how I would pick on my scalp until it would bleed. I would pick on it every day - let it dry and make it bleed again. It's strange to admit now, but I felt something getting released when I picked at my own skin. But picking on my scalp only lasted for a year or so (I don't really remember exactly how long). Then, I stumbled upon a forum topic on ear picking. This is something I have dealt with since elementary school, and still, continues on till today. I'm 17 right now. I pick on my ear almost every day until it bleeds. This is a normal routine for me, so I had never seen it as a problem. But when I read the posts online, I started to feel scared. Then, I started remembering how I would pick on my toe nails every day during a certain period of time last year. I would pick on my nails, and then I would grab a needle from my sewing box and try to remove the nail layers with the sewing needle. I continued to do this until I got scared of how much skin on my toe nails started appearing, and I put the needle down. I put band-aids on my toe nails and didn't wear sandals when I went out. But this habit stopped. I only have the ear-picking problem now. I was wondering if anyone else out there has used a needle or anything to damage their skin? I don't bite anything, I just use my hands. I was also wondering if anyone else let go of this habit naturally? Because I don't remember a specific time when I stopped picking my toenails or my scalp. It all seems like I had problems, but they all stopped at one point. I don't know if I should be worried about myself because, in fact, yesterday was the first time I was horrified at what I was doing. I can't figure out if this is/was a temporary problem, or if I really have dermatillomania. Help!