Just realizing ...

This is my first time here. I was sitting on my sofa picking on the bottom of my feet until they are bleeding and throbbing with the pain ... and I continued to do it through the pain until I felt relief ... and then I just stopped ... and the whole time I knew what I was doing was really hurting my feet, I will probably have pain when I walk tomorrow, and yet I will probably do it again tomorrow evening. I do it ALL THE TIME. I don't stop when it begins to hurt, I keep going until the pressure is gone ... sometimes leaving the bottom of my feet bloody and awful. And that's not all I do - I pick at my head ... my scalp ... I have beautiful long hair ... but I pick at my scalp because I feel like I have bumps and have to pick at them until they bleed ... and cause small sores and then I can pick at the sores until they bleed so they never heal. I went to a dermatologist for it because I thought I had a scalp disorder .... but they could never find anything that could be causing it. They gace me many types of acne medication, bacterial medication, etc...because the sores I caused were visible and apparent. I still do this. I don't know why tonight ... I thought maybe I'm not the only one who does this. So I was internet searching skin picking, cutting feet, etc ... and it said Self-injury. Is that what I have? How do I know if this is what I have? Can anyone help me to stop doing it? I would so love to be normal and live a normal life. It's almost compulsive for me ... like I feel relieved after I hurt myself to a point where the pain makes me feel like there is no pressure ... or helps me to stop feeling so sad. Am I strange for this?