Dyrant - (sorry if I just mispelled)
From what I understand, leaves are just like hair, once the damage is there, it doesn't repair itself. So you have to rely on the new growth to see if your going to be ok.

The thing I can say about working in Soil is that it seems to be VERY FORGIVING - so if you make a mistake (which I have certainly done a few times) you can fix it before it wacks ya!imp: