Hi Jamie,
First off, it completely normal to have an increase of pain once you start getting more aggressive in PT with a biceps tenodesis. I am almost 3 years post op from a biceps tenodesis, I was 24 when I had it done. I would get pain so bad it made me question all the time whether what I was feeling was normal or not. I also had a bioabsorbable anchor, just like you. It is normal to have internal rotation (behind back and even across chest) be the slowest range to come back, it's also a very uncomfortable range to stretch...but keep on that. I was still taking percocets for a few months after this surgery and the rehab from this surgery is one of the longer ones of shoulder surgeries. Be prepared for it to take close to a year for you to feel the FULL benefits of the surgery. For me, at 9 months I felt like I took a big turn in terms of full return to normalcy. 9 weeks is still very early in your rehab process and it can be very disheartening feeling what you're feeling, but I can tell you it will get better, and I think a lot of people here will agree with me. Also, be aware that it took me 9 months to start feeling much better, that doesn't mean it will definitely take you 9 months, it could only take 6 months. I just want you to be prepared for the timeframe.
Hang in there, try some heat now at this point when you start PT before doing exercises to help get warmed up and lessen muscle spasm. Not sure if you've tried anti-inflammatories, but it's unlikely your OS would do cortisone. I definitely wouldn't worry about another surgery at this point.
Hang in there, feel free to ask away here, lots of people have been through this.
Leanne