your nerve endings have been numbed by extreme weather, and have most likely compressed. Cold contracts, heat expands. The burning feeling after lukewarm water is the action of cold, stiff contracted nerves getting a)water and b)warmth. They are both expanding agents. Your hands have the largest amount of nerve endings relative to area second to your lips. I don't necessarily know that the burning sensation is an evolutionary advantage, it is a 'con' if you will, for the perk of being so sensitive...so sensitive that we can read with our hands and not our eyes...It truly is a miracle.