The difference between cold packs and hot packs is that they are applied at different stages of the injury, as follows. In the early stage of injury, mostly within 72 hours of injury with cold compresses. Because of the early injury, there are many small blood vessel rupture, tissue fluid extravasation, followed by swelling, cold compresses have the effect of vasoconstriction, reduce the role of oxygen consumption, for the control of local edema has a good effect. After 72 hours after the injury, vascular exudation is reduced, you can carry out local hot compresses, hot compresses can accelerate local blood circulation, you can promote the absorption of swelling and bleeding. It should be noted that the different time of injury, can not be indiscriminate use of compresses, if the early use of hot compresses, will aggravate the vascular exudate and tissue edema, in the recovery of the disease is not conducive. If any discomfort occurs during the recovery process, seek medical treatment promptly.