Stop all activity right away. Continuing to use a sprained joint causes significantly more injury. 'Walking it off' is a myth for sprains.
Apply ice wrapped in cloth for 15 to 20 minutes. Repeat every 2 to 3 hours for the first 48 hours. Never put ice directly on skin.
Wrap snugly — firm enough to feel supportive but not so tight it cuts off circulation. You should be able to slip one finger underneath.
Rest the limb on pillows above the heart. Even a few inches of elevation dramatically reduces how much it swells.
Ibuprofen or naproxen help with both pain and inflammation. Take with food.
Guidance only — in any emergency, call 911.