The saddest problem I see is self mutalization

Maybe I can shed some light on this.

Our physiology is complex.

Are you familiar with "runner's high"? The brain responds to the pain a long distance runner endures by dumping endorphins, which helps the runner endure the pain but also creates that odd feeling we call runner's high. In BDSM, this is referred to most often as "subspace".

A good top, the one in charge of the actions, can read his bottom and modulate the sensations between pain and pleasure such that the bottom cannot distinguish between the two. A sadist does not love giving pain to make people feel bad. He gives pain to make people feel good. And, there are plenty of women that top, also.

I've seen some interesting pics of artistic cuttings, but they are hard to find. Even fetish sites ban them over legal concerns. I can honestly say, it's not my kink, but some people get into it.