Hot packs should not be applied until 72 hours after a foot sprain. After a foot sprain, it is best to start intermittent ice packs as early as possible after the injury. Ice packs can reduce bleeding from the injured area and help reduce swelling. ice packs are recommended for the first 3 days after the injury. 72 hours is the acute phase of inflammation after the injury, and hot packs may cause inflammation to spread, which will increase blood flow and thus increase bleeding and swelling, which is not conducive to the recovery of the sprain. After 72 hours of chronic inflammation, you can only apply hot compresses to the sprained part of the foot, which can accelerate local blood circulation and promote the absorption of hematoma through hot compresses. Need to pay attention to the hot compress to avoid the temperature is too high, which will lead to burns. Sprained foot should be timely consultation, under the guidance of the doctor for treatment.