I was diagnosed with Papillary Thyroid cancer in January of 2021 when a nodule was found incidentally on a neck CT. I had a complete thyroidectomy a few months later. My surgeon said that the lymph nodes looked clear. The path report from the surgery said that the cancer was 1.5 cm x 1.5cm x 1.5 cm, encapsulated with focal capsular invasion, no vascular invasion, and margins were free of tumor. I was rated as stage 1b and told that I was very low risk, the only risk factor being my age which was 70 at the time. I felt very lucky. Getting the levothyroxine dose titrated was a challenge but all my blood work looked good for several years. My doctor said that he considered me "cured." Then suddenly there were slightly elevated levels of abs-thyroglobulin. My doctor ordered an ultrasound which revealed a thyroid fragment in the right surgical bed. A year later an ultrasound revealed a fragment in the left surgical bed as well. I knew there could be cancer cells remaining but I didn't know that it was common for there to be thyroid tissue remnants post total thyroidectomy. Sorry this is such a long introduction to my questions. My doctor no longer considers RAI to be a viable treatment option if the remnants start to grow (because he said "it ruins people's lives." I have read the horror stories.
Question # 1: Are there treatment options other than RIA if these remnants start to grow? My TSH #s were up at my last blood draw and for the first time my QT-thyroglobublin was slightly elevated. My doctor thinks the remnants are likely effecting the TSH.

Question #2: I looked back at my previous blood work from 6 months earlier and found that the brand of my generic levothyroxine had been changed by my pharmacy at about the same time. I have read that those changes can have big effects at times. My doctor didn't seem to think this was likely. My pharmacy says they can't get my previous generic, even if I pay out of pocket. Have any of you had this experience and if so, how did you manage it?
Bottom line: I don't know if the increase in my TSH this month was due to the generic levo changing or the residual tissue starting to play a role (or both). It seems there is no way to know. I'm fine for now, and we will redo my blood work in 3 months rather than 6 months, but having been told several years ago that I was very low risk/cured, the watchful waiting has me feeling more anxious.