I can hurt myself without paying for it. haha.
I've had a lot of self-destructive tendencies over the past two decades (basically since I was ten). Now I don't know if it's an enjoyment of pain, or a hate of the self, or a 'trying to feel something' motivation, but it happens.
Depression I don't believe is a cause, plenty of people are depressed and they don't self-harm or seek pain.
Asperger's, also, doesn't seem to fit.
Perhaps you're just a masochist? Or you find that it's the only thing that actually relieves your anxiety.
Personally, I don't think it matters what the reason is. Make wise choices as to the placement of these tattoos and piercings, and you'll have nothing to worry about.
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Be not angry that you cannot make others as you wish them to be, since you cannot make yourself as you wish to be.
~Thomas à Kempis
"Be plain, good son, and homely in thy drift;
Riddling confession finds but riddling shrift"
~Shakespeare