It may be chapped skin, which usually occurs in winter. The skin on the back of the hand and heel of the distal limb is cracked due to water loss or local low temperature, and even bleeding is serious.

If the scar you are talking about is convex and accompanied by stinging pain, it may be that you have been exposed to allergic substances, or some people have mild urticaria symptoms, and the same is true of epidermal traces. It is best to go to the hospital to see a doctor in internal medicine or dermatology.