If i had a kidney infection 5 years ago, was given antibiotics, how would you know the antibiotics cleared it? could they not have worked and just be seeing kidney damage and changes in blood pressure now?

A negative urine culture following appropriate antibiotic treatment attests to the clearing.of the infection unless all urine from the infected kidney is blocked from draining into the bladder. However one would be very ill with that degree of pyleonephritis and symptoms would continue. However severe bilateral infection can result in enough kidney scarring,eventual shrinkage causing hypertension