When temperatures tumble, it only takes a matter of minutes before you're at risk for frostbite. According to Cleveland Clinic's Doctor Andrew Yocum, frostbite can become serious and irreversible if not caught early. Doctor Yocum says if you notice your skin becoming discolored, white-hard or leathery get out of the cold quickly and begin passive rewarming. Be careful if you are using water when numb. It may be too difficult to tell the actual temperature and you don't want to burn your skin any further. When in doubt, don't hesitate to go to the hospital to be checked out.