I still have to resist the urge to pick at bug bites or scratches, etc. When I was a little kid I would dig at bug bites or sores to the point of getting them infected and bleeding, and even then I'd still pick. I don't think I was consciously being self-destructive, there was just something oddly calming about it which is really messed up. I have some pretty bad scars on my arms and legs from this.
I also used to chew my nails and cuticles relentlessly- until I started doing acrylic nails.
A lot of the time picking and such is considered to be a nervous habit, and I was really horrible about it as a child. I don't dig and pick like that much anymore - I noticed a real decrease in the desire to pick and fuss after I'd been on meds (Prozac and Catapres) for awhile. I also think I'm a lot more conscious of it now because I'm diabetic and anytime I get any kind of skin sores they take forever to heal and get infected really easily.
I also have an interesting habit of dropping off the planet now and again. I turn the ringer on the phone off, turn off any kind of social media, etc. and avoid communicating with anyone for as long as I can get away with. Sometimes that disturbs my family (a whole horde of loud, extroverted NTs...) even though they know I need to do that from time to time, they don't get it. They all come up with things like I'm dead in a ditch somewhere because I don't answer the phone for a day or two. Go figure.
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