I am sorry you are having issues so soon, but at least your surgeon is giving you a good reason for the continued issues you are having.
I had a revision in October and he replaced the femur portion of the TKR and of course, replaced the spacer. I was super surprised to find I didn't have near the pain this time that I had previously. I give a lot of the credit to the spinal and nerve blocks he performed. They made a big difference for me personally. I was off any assistive device the first week. I didn't drive for 4 weeks because I was nervous about movement of the right knee but when I did start, I was thinking I could have done it earlier.
After the first week, the only pain medication I took/take is Tramadol, Celebrex, and Tylenol. They have been enough for me but that is my journey and may not be yours. Especially with your RA, I am sure it is a different cup of tea to dealing with pain. Unfortunately, you won't know until you go through it!
I have performed ALL of my own PT. I did what the PT did previously without the pressure and pain they caused and I have done really well. With you going through your PT so recently, I am sure you know what needs to be done but of course that is your decision to make.
Best of luck to you!!