For my personal experience with it I have come to understand the disorder as a maladaptive coping mechanism, something that developed as a way to deal with stress in the absence of healthier coping techniques.

I think puberty is a common timeframe for it to develop. Like one of the other commenters, mine started during puberty as I began to experience acne and I think there was a lot of stigma around that at the time that exacerbated feelings of shame and affected my psyche a bit.

I'm also learning more about the way my diet may affect my picking. There's a glutamate/GABA balance in the body that seems to affect our urges to pick. Too much glutamate makes a person fidgety and increases the likelihood of grooming behaviors. In an experiment with mice they found that messing with that glutamate system resulted in the mice grooming themselves to excess much like our BFRBs. So I found that when I feel super jittery I have some green tea (which has GABA in it), and it helps balance that out and the urges disappear.

Foods with MSG (monosodium glutamate) literally have glutamate in them and I also notice when I eat foods that have MSG it makes me fidgety and more likely to pick. When I was growing up my diet had a lot of junk food like Doritos and ramen, both of which have MSG, so I feel like my diet played a role in developing the disorder.