MY 10 Year Old Fair Skin Son Has Redness Around

MY 10 year old fair skin son has redness around the knuckles of his hands and the redness is a little darker on one hand then the other. It almost appears to look as if he has placed his hands in very hot water and it turned his pale skin to a red/dark red color. He says the do not hurt but when I put lotion on them he said it burned a little and only seemed to make it worse. It started on one hand yesterday but now today both knuckles are red. Any ideas?