Conceptually, a good start to an idea. Technically, it leaves quite a bit to be desired. The lack of focus detracts from the shot and brings out too much of a "snapshot" characteristic for my taste. The sepia tone is a good choice, but unfortunately it's not enough to mask the haloing around so many of the high-contrast boundries. And with a bedspread that busy, a much shallower DOF would have served you many times better.
I like this as a portrait very much. The sepia tone gives it a timeless quality and the trouble expression is really wonderful. The harsh shadow where the hand is at the face is a little distracting - more fill light would help. The focus could be crisper, but it doesn't have to be completely sharp. It seems to capture the habit challenge well - more of the emotion of nail biting than the act of it.
I don't know if you wanted the focus like that, but I think it would have been better if it was in focus, but thats just my opinion. I like the expression. I think its a bit tightly cropped from the top. The choice of tone is good. Maybe tweak the levels to darken the whole photo a bit?