Habit or dermatillomania?

I'm Megan, I'm 20, new to the site, and I've been picking my thumbs raw since I was about 9 years old. It all started when warts appeared on the side of my thumbs. I desperately wanted them gone so I began to pick and pick and pick at them until they were gone. I don't remember the last time my thumbs looked "normal". Its exhausting, embarrassing, and painful. I dont even realize I'm picking until my fingers are wet with blood, my friend grabs my hand and makes me stop, or I get up and theres a small pile of skin on my lap. it's almost like my hands have a mind of their own. I've noticed I do it when I'm nervous or bored ...I guess my question is...Is this a habit that stuck with me or do I really have dermatillomania? And can anyone give some tips to help?