It looks like wet hair displaying natural parting / flow of hair. Dark wet hair on light skin will display scalp, especially where the the direction of the hair changes (plus wet hair clumps together). I know what you mean about the cold on the scalp, mine has always been like that, but I never lost any crown hair - I think it is just the position of the crown on the top of the head and ability for the wind to 'blow through' the whorl / cowlick area where hair can go in so many different directions.