Okay so nobody's volunteering maybe you should start a few more threads LOL? I don't know, but anyway what I would do is:
Immediately flush, but not super heavy, example if I added one gallon I would try to get a half a gallon run off (50%) that should stop or slow down whatever is going on (assuming you pH properly and other things are being done properly as well ?)
..where it's up at the top of the plant it's a little unusual, I don't want to give you the wrong information & I'd suggest you are careful whose info you take, but a flush is usually the least invasive thing you can do at this point, and it should help wash out whatever is causing this
Also damaged leaves don't survive at least not for long so whatever damage is there you can chalk that up because there's no real healing in leaves
When I get a chance I'll try to look into this more, there are people here who are really good at this, I'm not one of them, I would need information first, but if I can help I will but I need to look into it first and right now I'm running around, will catch up later but definitely the flush would be what I personally would do asap