There is not set amount of time for recovery of a sprained ankle. It depends on the grade or severity of the sprain. Some sprains are so severe that you might not be able to walk at all. You should seek immediate treatment at the emergency room or foot and ankle specialists’ office to make sure there are no broken bones. If you have a sprain this severe without a fracture, it will take some time to recover.
First you have to be immobilized in a device called a CAM walker boot and wrapped up to control the swelling and for pain. In a severe sprain, you will need crutches initially. The more you ice and the more you elevate, the faster you will heal. You will need to keep the foot elevated above the heart as much as possible throughout the entire day and night and ice for 20 minutes every hour when you are awake. An anti-inflammatory medication most likely will be prescribed to get the swelling down.
Once the swelling decreases you will gradually be able to bear weight on the affected foot within one to two weeks. Once this happens you may be taken out of the boot and switched to a lace-up brace to wear in sneakers and immediately sent to physical therapy to strengthen and help the stretched out ligaments heal properly. The therapy is two to three times a week for about 12 sessions for up to one month. For long-term stability, I usually recommend a functional, customized orthotic device (inserts).