I been biting my self inside the mouth all over and it doesn't hurt have been doing it for years can't seem to stop seem to like the blood. what is it?

Bad habit: Whether it is cheek and/or lip biting (like you) or nail biting, hair twirling, or any other habit, people often do these things initially to relieve stress. After a while they can "take a life of their own" and become a habit. Bad habits are hard to break and some people find professional counseling helpful in developing strategies to break a habit.

Cheek Biting: Seems like chronic cheek biting..Habit..Very common due to some sort of misalignment in your teeth, or perhaps due to TMJ disorder..See your dentist and get your bite evaluated..Sometimes its just a chronic habit you form because of doing some work while eating..Consult your dentist..