I have had a habit since a long time. A very bad habit, if I may. I never really took it seriously or even paid much notice to it since it wasn't harming anyone, not even me (in my opinion, at least). But recently when this was explicitly pointed out to me, I became much more aware of this strange and disturbing behaviour.
It even has a fancy term for it, it being a disorder and all. It's called Dermatophagia. It's not exactly self-explanatory, so here it goes. It's a compulsion of biting and eating one's own skin. I don't really enjoy biting my nails, but the skin right next to it, I do. I tend to bite it quite often when I'm alone. If I feel the urge to do it when I'm in a social setting, I try to tear it off with my other hand itself.
It's quite a disturbing practice because there is nothing of value that I get from it. The only thing I get is some satisfaction that I can't really explain through words. Even so, this satisfaction is something that I developed myself. Anyway, it is near impossible to articulate why biting off this hard and weirdly crunchy part of my body and then consuming it, is so good. And that's perhaps for the best. I'm not sure anyone would really like to know the details.
On a day when I have more time to myself to indulge in this practice without glares of disapproval, my hands look something like this:
This is still better than some other graver results of dermatophagia which I've seen. It can lead to excessive drawing of blood and even biting off of actual flesh. I have fortunately not let it come so far, but if I have let it come to what it is, even the most extreme case is well within the realm of possibility.
It hasn't come to this: 
There are way more disturbing images, but I'll digress. Digress to how it's not just about consuming it or biting it. But even the sensation of having the skin coming off of your fingers is so pleasurable. That's why peeling it off with my other hand works. But sometimes I want it to be neater, in which case I use a nail-cutter. I can hear the crunchy snip of the cutter. The skin is cut very neatly and with minimal blood. I then wait till the skin grows back to be able to do it again. For I don't enjoy taking it to the next level where there's too much blood because it scares me and I later regret it because the pain stings too much.
I have taken to this possibly as a mechanism to express my anxiety and perhaps to cling onto something concrete. Maybe there's some twisted reason for this involving my attempt to cling onto my own self and consuming it is symbolic? Maybe I'm afraid I'll lose myself or my identity? Or it's just anxiety, plain and simple. But what I do know is that it is critical to take measures to stop it before it's too late. It can start out small, but it will invariably lead to endangering your own health. If it's anxiety, then ensure you take control of it and make yourself aware. If it's situational i.e. you do it only in certain situations, then either try and eliminate such situations or find out the underlying issue for the same and control it. Point being, don't let it just fester and become worse.
I have been trying to cut down this habit for a while now. I have to a large extent cut off biting with my teeth. It's hard to cut it off completely, 100%. So I restrict it only to tearing it with my other hand. It's still progress. Not only is biting skin with the teeth more harmful because the teeth are sharper and it's easy to get carried away and bite off more than is healthy, but also it's quite unhygienic because the hands are supposed to have a lot of germs on them and putting them in the mouth might not be a good option to get some satisfaction in the long run. Using only my other hand to tear off skin has increased since it has taken over, but I have become more conscious of whenever I do it. When I'm conscious, it's easier to stop. And even if I do go on, I am careful to not tear too much and to ensure blood is out of the picture.
Use of nail-cutters are quite rare, possibly only when I'm actually cutting my nails. I have yet to make progress in that though. But over the past few years, I have made progress overall. There's much less blood and pain now. I still have to eliminate this disturbing habit from my system. Step by step.
Soon.