What treatment should I use for a sprained achilles tendon?

Rest, Ice, Compression, Elevation is recommended for almost all injuries. Ice the are for 20 minutes on and 20 minutes off for about the next hour or 2. This should help keep the swelling down. Stay off the foot. You do not want to tear the achilles tendon. That is very painful. However, I do believe that you should go see a doctor. It's important to know what grade sprain you have, so you can treat it in the best possible way.