When I find an edge that needs smoothing, a scab that I've let get almost healed, a place that's too rough inside my nose, I'm overcome by a feeling that I NEED to take care of it, and that removing it is a way to take care of myself. I've also noticed afterward, the brief euphoric feeling that comes with endorphins. Perhaps that self-medicated effect is part of what makes me associate picking with producing a sense of well-being, albeit a short-lived effect. Sometimes, if I notice the urge in time, I take a moment to notice my feelings of anxiety and just sit there with them. If the urge keeps building, then I'll look for another way to ACTUALLY take care of myself. Put some comfrey salve or natural beeswax cream on the place, and then relax for a moment. Sometimes I can relax enough to simulate the endorphin feeling.