Anytime you suspect frostbite, you really want to act quickly. You want to get that person safely out of danger. Get them out of the cold into a warm indoor environment. You want to wrap them up in warm blankets. You want to keep them warm. You want to put the affected body part in warm water. Water that is warmer than body temperature. Not hot, but warmer than body temperature. You want to submerge the limb into the water and you want to continually keep it warm. Once, as the water cools, just pour more warm water in there. Never pour water directly onto the affected limb. That could hurt it some more. If you're in a situation where you can't warm up completely, where you're afraid of the body part being frozen again, don't defrost it. Don't thaw it and then only have it to be refrozen. That causes worse damage. Call for help. Get someone there right away. If you're in a place where help's going to take a long time getting there, or you can't be in a warm place or you don't have warm water available, you can always put the affected limb in your armpit or in your crotch. Warm areas really, heat radiates from those places because they are your core temperature and you can help your friend or help yourself keep that limb warm. And finally, you don't want to rub or massage the frostbitten area. That could cause more damage. And you don't want to reheat the frostbitten area with dry heat like, a stove, or a fire or even a heating blanket. Because the person can't tell the heat and you could cause further damage. You could burn an already frostbitten area and you don't want to do that. Warm water is the best. Keep it nice and warm. It will slowly warm up. And get help.