Self injury-Please help me out and don't be rude

i have never done that before but i had a friend that would pick at her skin until she would make herself bleed. The doctor told her that there was a chemical in her brain that was released when she did this and that was why she found it pleasurable. It's the same thing as what the people who cut themselves feel. It releases something. I feel that way about tattoo's. I got one when i was really stressed and felt better. Then i got really stressed out and got the first one covered up and calmed down. I don't know exactly what it is, but i can guarantee that you probably are not the only person who does this. Some people pick at their face, some cut themselves, you pick at your gums. It is more normal than you think.