An ankle sprain occurs when the ligaments that support the ankle are stretched beyond their limits and subsequently tear. Most ankle sprains are minor injuries that heal with rest and ice applied to the area. However, some ankle sprains are more severe in nature, which means more damage to the ligaments. If your ankle is very swollen and painful to walk on (can't put weight on ankle at all), you need to see a doctor. If you do not receive proper treatment for a severe sprain, the sprain can weaken your ankle over time. Repeated ankle sprains can lead to long term problems, including arthritis, chronic ankle pain, and chronic ankle instability. The condition of chronic ankle instability involves the outer (lateral) side of the ankle "giving way," and often develops after recurrent ankle sprains.