I have had this weird mark on my thumb/knuckle for six months now. I thought it was maybe fading a bit over Christmas but it's now come back. It isn't a mole, it's more of a flat yellow discoloured patch that feels a little rough. No creams have made any difference. Would you see a gp in case it's skin cancer? I'm worried I will look silly going in about it but it won't go. The picture doesn't show how yellow it is really and I'm anxious it could be something sinister. I just want to forget about it but everytime I notice it its niggling at me.