Thanks for your query,based on the facts that you have posted it appears that you have UTI following endoscopic excision of polyp from the bladder .
The irritative symptoms that you have are due to raw area created due to excision of polyp and will go away once the wound heals up .
Please take broad spectrum antibiotics like Cefotaxime
along with anti inflammatory medication like Diclofenac
twice daily .
Ensure to drink more water.To keep your urine dilute This will help to control dysuria