Just reading a thread about someone's DC biting the skin around their nails, and sort of following on from there, lots of things seem to fit. I used to compulsively bite the skin on my thumbs, I think in my early teens, and I also developed a habit of doing a sort of fast head-nod-shake thing, just a small movement but noticeable. My mum was always telling me off for doing it. I managed to stop myself doing the head-nod thing, but switched from biting my thumbs to biting the insides of my cheeks and lips, and picking at my gums with my fingernails. I still do it. My dentists have always mentioned my 'receding gums' but give me the
look when I say they're not actually receding, I picked them until they stopped growing back. 
When I was in my late teens (uni and starting work) I had to re-lock my door several times and turn light switches on and off and turn taps on and off until they "felt right", I can't explain it really. If I had to step around something for a reason - like, padlocking my bike - I'd have to step back round it the other way to even things out. I don't do these any more. But sometimes if I touch something, I have to touch it again.
Something I still do, is that if I get a glass of water from a tap I have to splash the first bit of water in the glass and then empty it, before I can fill the glass. And whenever I lock a door - house, car, shed, anything - I have to pull the handle afterwards to make sure it's locked, even if it's a visible padlock that I've just snapped shut.
It's a really stressful time right now - house move - and tonight I realised I was doing the head-nod thing a tiny bit. Which makes me a bit worried that these things are not 'gone' but just lurking somewhere. I don't really know much about OCD but on a quick Wiki search, these seem to fit the bill.
God, that got long, so sorry! 