Hello and welcome to the forum. I am happy to hear that the diagnosis came back with a good report.
I had the wash after my TURBT as well (that is pretty much standard these days) but no reaction to it at all. Everyone's body is different as to what upsets it. Glad you are on the mend. Some of your off and on pain now could just be from the irritation caused by the scraping.
I hope things are smooth sailing from here and let us know how your future check ups go. We are great cheerleaders!