Suggest Treatment For Itchy Dark Skin On Buttocks

HI! BETWEEN MY BUT CHICK IS GETTING DARK COLOR LIKE KIND OF GREEN AND ITCHES A LOT SOMETIME, I WAS COMPLETELY PINK BEFORE AND NOW SOMETHING IS HAPPENING, I HAVE BEEN UNDER A LOT OF STREES FOR THE LAST 9 MONTH AND STARTED 7 MONTH AGO, I HAVE IT ON MY PUBIC AREA WHERE YOU YOU SHAVE OR WAX, CHANGING COLOR, WHAT TO DO? OR WHAT IS GOING ON? THANK YOU!!! MACARENA