I do think that to do that to yourself you have to have some deep rooted issues, what they are I haven't a clue, but I don't think a rational mind would choose to disfigure a part of his/her body to the point where it is dangerous and/or no longer functional.
But, one person's issues are another person's natural psychological makeup.
These things only become issues when they're labeled as being "different" from what is normal.
And what
is normal? Who asserts when something is abnormal?
It's all subjective.
Usually, something is considered abnormal when it is in a minority. In actual fact the only things relevant are law and harm. In that as long as it harms no one else, people can do what they wish.
If we follow the rules of psychology, I'm sure he's been told he suffers from Body Dismorphia (sp?)
In actual fact it could just simply be that he enjoys the process and experience of extreme Body Modification.