I have noticed a large dark spot on my heel recently. It s not painful, it s not difficult to walk or stand but I do not remember to have had any trauma to cause it. I spend a lot of time standing cause of my work but that has never been a problem. Can this be melanoma or some other kind of serious disease. Im not sure if this is related but I have had a low grade fever everyday since I had covid a year ago. All my blood tests came back fine except a very mild uti which im treating with cyperus.