Frostbite causes inflammation of the subcutaneous tissues, and if the temperature rises, the inflammation will worsen as blood vessels dilate and blood increases in speed, and the increased inflammation will stimulate the peripheral nerves causing itching. Temperatures lower than the minimum temperature that the skin can withstand will cause frostbite, frostbite is actually an inflammatory response of the body, if the body temperature rises after frostbite, it will cause the local frostbite blood vessel dilation, blood flow speed up, and make the inflammation spread rapidly, the body experience at that time is itching. So after frostbite should not use too high temperature on the skin, you can make the skin temperature slowly rise, the skin will cause less damage. The most effective way to prevent frostbite is to avoid staying too long in a cold environment or exposing your body to too much cold.