Hi there, pulling hair and nail biting are issues related to anxiety
level. They are also sometimes seen with obsessive compulsive
behaviours. Fortunately there are good medications for these conditions. You can ask a doctor
to evaluate your situation to see what medication could be the best for you. There is no need to take the medication life long, but it is necessary to take it for a period of time. Some cognitive and behavioral technics like impulse control are also useful and you ask you doctor about. I wish you a good health.