First aid for sprains and soft tissue damage, use RICE:

• Rest it. Try to reduce walking, driving, activities that put a load on the ankle
• Ice it. Cold reduces swelling and can help with pain.
• Compression. Use an elastic tube bandage or an elastic roller bandage to support it and limit movement while it rests
• Elevation. Put your feet up for a few days and catch up on tv

I’m not a doctor, just a random person on the Internet.