What happens to the scar tissue within achilles tendonitis? is it forever a weak spot?

Have it treated: Tears in the Achilles or chronic inflammation can result in scarring, which is not as oriented or as strong as the natural tendon. Many are using fat-derived stem/stromal cells plus platelet-rich plasma to be placed (via guided ultrasound) within the shealth of the tendon. New tendon often results which is stronger and flexible like original tendon tissues.

Depends: It depends on the amount of soft tissue destruction. If the inflammation is controlled, soft tissue destruction and scarring should be minimized.

Yes: Scar is always weaker than uninjured tissue but the difference is often not functionally significant. The achilles tendon is one area that is subject to the greatest torque and shear forces by virtue of the weight carried in this area which makes it particularly more vulnerable to repetitive trauma.