Picking cuticles to the point of bleeding

How do I figure out the thought when I seem to be doing things mindlessly? My husband often tells me to stop picking my cuticles and I didn’t know I was doing it. Picking my cuticles should go in the A line I think but I don’t know the thought. That leads to the feeling that leads to the action of picking.

There are times when I know I am anxious and become aware that I’m picking them on my own, I can figure out the thought leading to the anxiety if I do a model on those situations. But other times I will be watching a TV show, in a work meeting and seemingly paying attention to external stimuli but also picking to the point of making myself bleed before I notice I’m doing it or my husband alerts me. How can I determine the thought if I seem to not be thinking at all?