What's my problem?

I'm 32 years old and have been picking/biting/eating my cuticles since I was 10-ish (when I stopped sucking my thumb) and I'm so ready to stop. I quit biting my nails, I quit smoking cigarettes, I even quit smoking meth (a decade ago) just through my own willpower but I cannot stop picking my own fingers. I had acne until I was 30 which I picked at and left scars on my jaw/neck but it went away when I got pregnant. I hope it doesn't come back when we stop breastfeeding. I'm too old for acne! I've managed to stop picking for short intervals by keeping my hands busy knitting but with a very attached toddler, that's not really possible. I've also been able to stop picking by having acrylic nails; they're too thick to get under the flakes of skin or scab but then if i have a really tough day I grab tools to pick with instead. How do I get down to the bottom of what I'm so anxious about?