IDK!! I feel so bad. Looking back, it was such a dumb decision to try to do a long-term transition. I wanted to go natural but I should have never attempted to transition. I knew that I could never cut my hair off and rock a fro so since I had seen others on the board do a long-term transition and since my hair was long, I thought I could handle it by just wearing buns.
I won't try to transition again until I am ready to just cut my hair off. Which, at this point seems to be never.
I was going to suggest a BC since your ultimate goal was to go natural, but I guess you don't want to look like you have natural hair...I'm confused by this.
Anyway, I think a cut is needed...you might be at neck length but in the long run it'll be much easier to look at thicker, shorter hair than the hair you are left with now. Most of the time I think posters are over-reacting when they have a set back, but the difference in your hair makes me really feel for you.
Good luck with whatever you decide.

sorry to hear about your setback. You've received some sound advice from this thread
So sorry that you're going through this. I wouldn't do a corrective personally as your hair has already gone through enough trauma. I would just do plenty of protein and moisture DC's, get a good cut and incorporate low manipulation bunning to kick start your recovery.
. Anyway good luck, I'm sure your hair will be back to normal in no time!