Kathryn, a sprain is a ligament tear not a tendon tear, and sprains can take significantly longer than 2 weeks to fully heal. The swelling of a sprain is not the "muscles getting bigger to protect the tendon" but increased bloodflow and lymph  at the injured area to promote healing. But you are right about tendinosis vs tendinitis. Ecxcept that ice has been shown to improve tendinosis because it resticts the associated formation of abnormal blood vessels.