If it was over watering, the entire plant would be affected.
This is severe nitrogen toxicity from feeding too much or too often...........or both.
Plain water until she recovers is the only real option.
When you finally resume feeding, half of what you were giving previously should be a good place to start.
"Flushing" with huge amounts of water can make things worse, by releasing even more nitrogen from the substrate, increasing the problem, not helping the issue.