Lol, I certainly don't collect bits of it. That made me think of Hannibal Lector and that other guy in those movies for some reason... the one who makes things out of the skin of the women he kills.
As to eating it, if I do it is because I have chewed rather than pulled at it by hand. Anyways...stress/boredom habit. I have many. The other main one, which migth be a stim I think, I have had since I was 11.
I pull my eyebrows out. Anytime I am bored, stressed, thinking etc, I find my hand going up to there automatically, and it is incredibly difficult to stop.