HI bud.
First off, the tips being yellow is not necessarily something bad. It can be a sign that the plant has reached the very beginning stage of a nutrient burn. There's nothing wrong with that as long as you act accordingly.
Sorry to hear all the troubles you already put yourself through. Dunno how to break it to ya, but damage is permanent.
The yellowing of the tip will stay throughout that leaf's life and either get worse or stay the same. The latter of the two meaning, you listened to your plant and only gave her what she can process from here on in.
The tips pointed upwards like that can be an indication of a few things. Heat/light stress, soil is too hot, rh not in preferable margin, ph out of balance, etc... once you get conditions stable again, they should relax and hang comfortably again.
Hope this helps, even just a little.