Wow I get that too, I mainly pick at my arms, my lips and my scalp. I tend to wear long sleeve tops for this reason, because in the past people have asked me what is wrong with my arms and I didn't know how to respond to that. For me, I think it is a symptom of my anxiety. I'm not sure how to advise you on whether you should tell anyone, because honestly the only people who know I do it are my family. But maybe someone would be able to help you stop doing it? Idk sorry