Presuming you don't have any more recent version of your animation saved...
Do you have a previous version of this model saved? A version that is that same as what you started this animation with?
(I don't want to hear "no" as the answer. )
If you do, make a copy of it. Rename the copy in some way. Load it into your objects folder.
then, in the chor, in the properties for the model, change the "shortcut to" to the name of your renamed imported model.
Now you have a proper, undamaged version of your model in the chor.
Scrub through it and delete or redo any keys you made after you changed the hierarchy in the first model.