I have a hamstring tendon avulsion. I've had physical therapy, but after six months it continues to hurt. What are my rehab options?

Depends. That would depend on the location of the avulsion . It might be repaired or observed depending on the location, duration and activity level of the patient.
Eccentric training. The best evidence comes from norway which would suggest eccentric strengthening program where your hamstrings work while they are getting longer.....Example is kneeling then slowly lean forward.