How to recover a corrupted Zsh history file from memory

For reasons that partially escape me (and are outside the scope of this question), my Zsh history file became corrupt. I have several sessions open that have the history in memory. Is there a way to recover the history file (in its correct format) from what's in memory?

While the output of the history or fc commands looks like this (by default, at least)

57694  type -a ssh-keygen
57695  ssh -v localhost

while the file is in a format like

: 1545938685:133;vim ~/.zshrc
: 1545938820:0;exit

(Obviously these are not the same entries—I just give them to display the format, and therefore the problem I'm facing.)

Is there any way to get fc to display all the data that I would need to recreate the history file as it was before it became corrupted?

(If this is not possible, I can recover most of it from a backup drive, of course, but I would rather recover all of it, and it would be useful to know how to do this in the future.)