mutilate
/ˈmyü-tə-ˌlāt/
verb
to cut up or alter radically so as to make imperfect
to cut off or cause severe damage to a limb or essential part of
The child mutilated the book with his scissors.
noun
the act of inflicting injury or disfigurement to one's own body; specifically : the act of purposely hurting oneself (as by cutting or burning the skin) as an emotional coping mechanism : self-harm
The original wound reopened and became dangerously infected, and yet this classic display of canine self-mutilation continued.