No urination for last 18 hours. Can do?

My dad is post Covid and had a uro bag put in as his urine was leaking. The urologist advised as a case of neurogenic bladder where it was getting filled like a balloon and then overflowing which caused the leaking of urine. The bag was there for about a month (it was replaced time to time in between) and yesterday we got it removed yesterday around 12 PM to see if the control over urine had come back. Since the removal, my father's bladder has got full and his belly appears swollen. Very less urine has come out with a burning sensation. He has discomfort in his belly. My questions: - Is the burning sensation normal? - Is it advisable to put in the uro bag again to help him relieve his discomfort in the short run? - Can nor urinating result in urine passing back to blood stream or cause infection? - What is the maximum damage this condition can do? Note: His BP is somewhat normal (131/81) but sugar appears to be high (130 Fasting)