Just found out my daughter is picking her feet

As a child, I used to pick the bottom of my feet until they would bleed, and would sometimes chew on the pieces of skin (gross, I know). I don't remember why I would do it, but I remember being completely ashamed anytime someone would notice and ask me what I had done to my feet. I would always make something up, like I would tell them I had a blister, or I had cut myself on a piece of glass. I don't really remember when or why I stopped, though I have continued to chew and pick at my cuticles, even now. I just found out that my 10 year old daughter has started picking at the bottom of her feet, too, and I don't know what to do about it. She came to me tonight because she had started to pick a piece of skin and it had gone too deep and started bleeding, so she got a pair of scissors and cut it off. She has a 1 inch long hunk of skin missing on the bottom of her foot now. I talked with her about it, and she said she has been doing it for awhile now, but it had never bled before. I don't know what to do for her. She has an autism spectrum disorder, as well as moderately severe A.D.H.D., and she is on stimulant medication for that. I don't know if maybe that can make picking behaviors more intense or what. I'm just kind of at a loss as to where to start with this. I don't know if I should try to help her myself first, then take her to the doctor if we can't come up with another outlet for her, or if I should just take her to the doctor now. I really don't want them to put her on any other medications, especially antidepressants. I just don't know what to do.