Frostbite, First Aid 

Frostbite most often occurs on skin exposed to cold, such as on the face or ears, and on extremities, such as fingers and toes.

Skin that is mildly frostbitten may look either reddened or white. When frostbite becomes more severe, the skin may appear blistered and possibly blackened. In severe frostbite, the skin typically feels hard to the touch.