How long will a class 3 everted ankle sprain take to heal? how should i treat it? and why does it feel like it burns after i walk?

Eight weeks: It will take eight weeks to heal and two more weeks to do functional rehab. If it is a true grade three the swelling will last 3 months. I treat grade three ankle sprains with a cast for 7-10 days, and then an agressive rehab program. They should be taped to resume athletic activities.

3-6 months: This is a severe injury. Early immobilization in a cast or "boot" is important. Non weight bearing is helpful until you can ambulate pain free. A comprehensive rehabiliation program is important to prevent repeated injury.