Ice packs generally need to be applied a short time after a tissue injury, usually about 20 minutes at a time. Ice packs work by preventing blood vessels from dilating, reducing localized tissue swelling and bleeding, and also avoiding excessive pain after the injury. Each ice application lasts about 20 minutes and can be applied once every 2 to 3 hours. However, when using ice packs, it should be noted that they are usually used within 48 hours after the injury, and hot packs need to be used after 48 hours to promote hematoma absorption. If there is a localized injury, it is not recommended to use ice packs to solve the problem, it is recommended to consult a doctor in time to prevent fractures and other serious injuries, and take standardized methods of treatment under the guidance of the doctor to promote the alleviation of the condition.