Urethra bulge

Having uterine cancer, I had a total hysterectomy in June, 2009, done robotically.  Also, had a pelvic sling put in at same time.  Sling helped urinary incontinence when sneezing, coughing and lifting--but not involuntary leakage.  Had coaptite injections in the upper urethral area in March, 2010.  No relief with that.  Had macroplastique injections in September, 2010.  Helped leakage tremendously.  January, 2011 found a urethral bulge while showering.  No pain, discomfort, tenderness or any other issues with it.  Oncologist check-up recently suggested calling urologist about the bulge.   Urologist says no big deal.  Mentioned prolapse.  Prescribed Premarin to be applied topically directly to the bulge 3x a week to make it shrink.  

Considering it was 18 months after the hysterectomy and sling, did the surgery encourage the bulge?  Or did the injections for incontinence possibly cause it?  Is the topical Premarin the normal action to take for the bulge?