It can be treated at home. Remove all wet clothing. Wet clothes draw heat from the body. Don't let the child control the water temperature. Numb hands won't feel the heat and can be severely burned by water that is too hot.
Frostbite is characterized by white, waxy skin that feels numb and hard.
It requires emergency medical attention. If feet are affected, carry him. If warm water is not available, wrap gently in warm blankets. Do not use direct heat such as a fire or heating pad. Do not thaw the area if it is at risk for refreezing, which may cause severe tissue damage.