Compulsive:

Compulsive self-mutilation is a usually subconscious act frequently observed in patients suffering from obsessive-compulsive disorder. The most studied form of superficial/compulsive self-mutilation is trichotillomania or hair pulling. Some who suffer from this compulsion are completely unaware of their actions. Others have specific ways in which the behavior is performed. For example, they might pull out an exact number of hairs from each side of the head. However, compulsive self-mutilating behaviors do not necessarily indicate a pathological state.

The most common behaviors exhibited by people suffering from superficial compulsive self-mutilation are non lethal and non threatening. The symptoms most often observed are hair-pulling, nail-biting, and the picking and scratching of scabs and skin.