Day 45: She's going through something right now. Rust spots and brown tips. Could be the watering, the feeding, I'm not sure. I'll ask my grow buddies!
...I flushed her and now I'm crossing my fingers.
Day 50: she's recovering
I'd say yes.
So there's an EXCELLENT full tutorial on GrowWeedEasy ill dm it 2u..
But the zist of it.
Take each node. And at the tops make sure to leave 1-2 sets of fan leafs for energy uptake and to leave sets at the very end of that node. Then going through the middle you can take any major fan leafs off once the nodes above them have grown out some. As the longer you leaves sets of fans under shoots the more said shoots will grow. So to make colas. This site is excellent. Ill send it to u know.
It is a full tut on Defoliation for the whole phase of ur fens
Nute burn, not only Nitrogen toxicity, but some others too.
Would heavily reduce or stop feeding for a bit. Plain water diet shoult sort things out. Damage wont go away, but wont progress too.