A sprained and swollen foot with a hard lump on the back of the foot may be caused by a subcutaneous hematoma due to a sprain, or it may be due to ligament damage or fracture, for example. Treatment mainly includes conservative treatment and surgical treatment. 1. Conservative treatment: for subcutaneous hematoma caused by sprain, in the acute stage, the affected limb should be braked, iced, and elevated, and if necessary, it can be immobilized by pressure; after 72 hours, it can be heated, massaged, and treated with physiotherapy to accelerate the blood circulation, and to promote the subsidence of the hematoma; and it can be orally taken to promote the venous return of the medicines such as Diosmin tablets. 2. Surgery: For hard lumps due to ligament injury or fracture, first of all, imaging examination such as X-ray or MRI is needed to clarify the location and severity of the injury. Surgical intervention may be required in cases such as ligament rupture or poor fracture alignment. Surgical procedures include ligament repair, reconstruction, and internal fixation with incision and reduction. The exact surgical procedure is determined by the patient’s original condition. If the patient’s symptoms are severe, or if the symptoms persist without improvement, the patient should go to the hospital for treatment. The above medications need to be used under the guidance of a doctor, avoid self-medication.