What Causes Frequent Urination After TUR Surgery?

I am a female. I had bladder cancer tur surgery on Sept 30, 2014. Three cystoscopic exams since show no return. The cancer was lowest grade/stage. I suddenly have a slightly sore and very RED urethra. Also, my doctor has not done anything, but since the TUR surgery, I have to urinate far too much. Never had the problem until after tur surgery