I'm a compulsive scab-picker, and insist that scabs SHOULD be picked off. My reasoning was proved correct when I recently picked a scab off the top of my foot, and felt it move in my hand.
I immediately took it to my binocular-beam microscope, and saw that it was in 3 'layers'. After I prised these layers apart with 2 x 30-gauge needles, I couldn't believe my eyes when an insect (or other type of animal) around 8mm in length crawled off; I was so surprised that I didn't have the presence of mind to catch it before it left my bench, thus finding it pretty much impossible to find due to the messiness of my lab.
The scab actually had the top of this creature's head and the tip of its 'tail' poking out before I broke up the scab, but I didn't think anything of it at that time.
Unfortunately, I have been going through a period of parasitic infestation recently, and I'll make another post about the other places I have had creatures residing in.
Nothing on the internet, so any info would be greatly appreciated.