As just another kook discussing medical issues on the interwebz I'm here to commerisate rather than offer actual medical advise. I've been dealing with glute tendonitis for sometime. I too had a surgery in the region (FAI - hip preservation surgery). Initially I thought I had an issue with my back, but my glutes turned off, probably due to the hip being trashed and another underlining issue I have with my SI joint. I addressed the glute issues before my surgery. After the surgery I continue to deal with the glute issues and am religious with my PT exercises.
It took my PT less than a minute to catch the issue. Specifically my glute medius and glute maximums had shut down. This put A LOT of strain on my piriformis. This pissed the sciatic nerve off. My IT band also overcompensated. A real mess. It was mostly adduction that really got things ramped up. My lifestyle is what overdid it.
I absolutely had to take MONTHS off. I stuck with a strict PT regime. I went to each session with a detailed description of symptoms.
Again take these bullet pts w a grain of salt. Maybe you have addressed these things maybe not, I'm just offering the major points I was dealing with that you can think about before your next PT appt and possibly discuss with a professional. Im sorry to hear you only have one session left.
-Adduction vs abduction (which triggers pain and makes the tendonitis worse)
-to stretch vs to tighten (the muscles/tendons/etc.)
-isolating specific muscles
-nerve gliding
-foam rolling
-heat vs ice
-massage (who doesn't love a butt rub?)
Good luck. Feel free to DM me. I don't want to offer up exactly what I was doing/still do as far as PT on this thread as it could make things worse for someone else dealing with glute issues.