I've actually done the exact same thing a couple of times, I had a 'blind' mole on the top of my lip (it was a very light brown mole and not at all noticable unless someone stood right up at my face) but it's something that really bothered me and it's not grown back and there's luckily been no scarring from it, I also have one just under my chin and again, is a 'blind' mole but keeps coming back everytime I pick at it. So you're not alone with this mole picking/tearing off problem!