RICE is an acronym for Rest, Ice, Compression, and Elevation. If you injure or strain a muscle or tendon just use RICE to treat it:

Rest - An injured muscle needs at least a few days of rest to repair itself. Do not engage in strenous activity or anything that could reinjure the muscle.

Ice - Apply an ice pack or cold compress to the area several times a day to releive pain and swelling.

Compression - Wrap the injured area with an Ace Bandage or other elastic bandage in order to control swelling.

Elevation - Elevate the area of injury whenever possible to reduce the collection of fluid and reduce swelling.

You may also take an anti-inflammatory such as Advil or Aleve, or a natural alternative, for a few days to help with swelling. Seeking the treatment of a massage therapist who specializes in injuries can also help speed the healing process.