Paula, your diagnosis is as good as it gets for bladder cancer!
Congratulations!!!
As for the burning, the antibiotic probably won't help and isn't for that. The burning comes from irritation due to the nature of the procedure. Tubes were stuffed up a passage that just ain't used to such things. So of course there is some irritation. It should disappear in a day or so. I usually experience this after each cystoscopy and BCG insertions.
ANYTIME a foreign object is placed in something such as your urethra, there is a chance of bacteria being inserted so matter how careful the doctor and his staff are. Cipro, for example, is routinely given after such a procedure. In your case, because of your allergic reaction, a different antibiotic is being prescribed. Be sure to take it as directed until it is all gone!!
You definitely do not want to end up with a urinary tract infection now!!
You are doing great, kiddo!!
Sara Anne