Frostbite,

Cooling of  fingers, toes, ears, nose, etc can be a serious injury, this sometimes goes unnoticed by the casualty, in order to keep the core temperature at a safe level, the body constricts the blood vessels supplying the peripheries and if prolonged, ice begins to form in the tissues, starting at surface level and working inwards. Deep frostbite damages tissues beyond repair.

pain may be felt early , hot aches as the blood supply returns , numbness, cold, patches of white/waxing skin which can be hard to touch,

Treatment,

protect skin with dry soft bandages, try and protect from further freezing, warm with body heat (not direct heat ), do not rub skin or give alcohol , and seek medical attention.