bladder cancer very confused!

My 58 yr old husband had a cystoscopy today as he had some blood in his urine and groin pain. There was something there doctor defined as a "red blob" he wants to wait four weeks and do another cystoscopy before deciding on a biopsy why do they want to wait four weeks? I'm so worried we thought it was something minor and then cancer got mentioned or testing for cancer does anyone have experience of this?