If you are in anyway weak stomached, this post may not be to your taste.
Since about the age of ten I have, with various pauses and breaks, religiously torn the skin off my left thumb. Why my left thumb? It is the one that the skin splits and blisters on the most. I remember then I was younger it was both thumbs, and occasionally my feet, but now it is almost exclusively my left thumb (although my feet aren't beyond reach).
It doesn't require too much effort either. I don't need to chew it or wet it, recently there's still old lines,where I was able to reach the maximum expansion of weak skin before it either tore to a deep spot that was too sore to continue or I couldn't get purchase with my nails, while I have been able to start new expansions on newly formed skin that's already 'white' and ready to lift. It often starts along the creases of the tumb joint, where the skin will naturally begin to break as I bend my thumb in numerous ways.
Sometimes only the very too layer comes away, sometimes multiple layers come away in one go. While strips, both shallow and deep, usually don't led to deep blood drawing damage, but once it narrows at one end, I usually expect the pinprick pain as it tears deep and does draw blood. That's not to say, often on my feet, that a broad stretch will with open a deep strip of blooded flesh or again multiple pinpricks, wells of blood that sting and cause reduction in function.
I am so adept at striping skin that I can do it one handed, while driving. Of course water helps and I often find myself in the shower helping it along.
Whyi do it is probably more interesting, and my main answer is I don't know. I am sure it falls under some sort of self harm and I have never spoken to a professional about it. The girls in work know about it, although we never discuss it. My parents know about it, as does my partner.
I often fob it off as a burn, stress, but mostly it's habitual boredom. It provides a feeling of release as much as it is entertainment. I don't stop until my thumb is either stripped or it has become to painful to continue. It is almost as if I trance when I do it, oblivious to the world around me, focused solely on the destruction of my thumb. As soon as I'm done I get mixed feelings, there's relief, freedom, satisfaction, but these are often overridden by shame, disappointment in my inability to prevent myself from destroying something that belongs to me, and a small pile of skin flakes that remind me of what I have done. Mixed with these are a confusing feelings of pride, pride at how much I have removed, how big the flakes are and how my thumb feels. It no longer has a ridges texture, after years of the tear heal cycle, it is smoother than my other fingers,
I suppose I should be concerned, worried about health implications and social implications from what is essentially self harm, but I never am. I just let it heal, with not real attempt to hide it any more, no real discussion of it, I have found this post hard to write simply dpbecause I lack the language to describe both the physical process and the feelings that ensue from it.
The photo below was taken as soon as I had finished an opening. It's raw and painful, but sometimes these things need to be shared.

