It sounds to me like a form of self-harm. It may seem weird and gross but its a way of dealing with stress/calming anxiety/producing a sense of satisfaction/whatever it is for you. I understand, I was (and to a certain extent, still am) a cutter. I did it because, like you said, it made me feel better, gave me a sense of accomplishment and satisfaction.
Do you find that you do it when you're particularly stressed or really anxious? The best way I have found to cope with self-harm is to identify when and why I do it and replace the negative act with something more positive. When it got really bad, when I knew that I might want to cut, I'd write the phone number of my friends on my ankles (where I did most of my cutting) so that when I did want to I would see their numbers, remember that I had people around me that loved me and that I didn't need to cut to feel better. This might not work for you, it depends on what triggers you to pick your skin. But I know that if you find out what makes you feel like doing it, it will be easier to make yourself stop!

M