Why would platelet rich plasma therapy be good for my damaged tendon?

Many reasons: Prp is a promising therapy for treatment of tendon, muscle, and bone damage. In this therapy, platelets isolated from a person's own blood are injected around the damaged tissue. Platelets contain numerous chemicals that break down damaged tissue and stimulate new blood vessel growth, bone production, and tissue growth.

Maybe good...: The theory is that the body can't on its own get enough healing or growth factors to the area (tendon), but concentrated platelet injected there enhance the nutrients and growth factors to allow the body to heal it. While many doctors do this, the most robust scientific trials (randomized controlled trials) have been ambiguous as to if it really works. Insurance probably won't cover it (check...).