I don't think that the scarring is anything to be unnecessarily worried about. Unfortunately, after repeated infections and such it happens naturally to try to repair the damage. Anyway, as long as the blood tests that indicate kidney function are normal, then I would not be unduly concerned. These would be you creatinnine and urea levels and also if your blood pressure is within normal limited.
If you have both kidneys, then if one kidney becomes slightly damaged and underfunctions, then the other kidney will take over a lot of the function. You can live perfectly well on one kidney.
Hope this helps?