Suggest Medication For Discolouration And Swelling Of Ears Due To Frostbite

Hi I got frostbite on my ears this Saturday night and experienced a clear blister Sunday and swollen and redness on my cartilage. Today it is purplish and possible blackish in an area, with a a stiff texture to it. Are these the symptoms of severe frostbite and should I be concerned about gangrene ?