J.G.
My daughter who is now 10, did this when she was about the same age. She was almost bald on one side of her hair. We cut it all short and as it grew out, she no longer did it. She has sucked her fingers and now bites her finger nails. She is a great well rounded, Social kid. We tried to pony tails and all that, nothing worked. When she sucked her fingers we talked and tried to yucky tasting stuff. She stopped when she was ready.
Just keep an eye on her. :D