Picking and biting habits

Hi, I have a habit of biting and picking my tongue. At first I do it subconsciously, and then when I realise that I am doing it, I spend ages, sometimes hours, trying to bite/pick off particular spots on my tongue. It is quite painful, yet somehow satisfactory, and more often then not, my tongue bleeds. Then I leave my tongue to start to heal overnight, after which there will be white marks all over my tongue, which I bite/pick off and the process starts all over again.
While this may sound a silly habit, it's been going on for far too long now (over 10 years) and I would like it to stop.

I also have a similar habit of picking the skin underneath my thumb nail with a needle. This habit I hate even more as it is physically noticeable. I bite my nail down until it is barely even there, and then concentrate using a needle to pick out the skin until it all looks smooth and at one layer. This is also strangely satisfactory, but I would like it to stop as it is embarrassing. It isn't painful as I have been doing it for so many years that the skin has hardened, but it looks disgusting and also takes up a lot of my time.

Both habits started at around about the same time, somewhere between the ages of 7 and 9, and I was wondering if there was anyone else out there with the same problem? Particular with the thumb nail picking.