I get those also on my hands and especially my left forearm. I am right handed and don’t know why I get them mostly on the left side. I think it’s because my left arm is more exposed to the sun ( over the years while driving , I am now 76). My doctor says it’s purport and my skin is thinner as I age. He told me not to worry. Haha! I use cream for crepy skin but don’t like to put creams on in warm weather. I’m going to look into the arnica