There are lots of choices, but I’ve highlighted the one you want: Recover Text from Any File. Click “OK” and you’ll see lots of junk, typographical notations, and other miscellany. In the middle of it, however, you should be able to find all your missing text.
When I deleted some text from my test file and did this procedure, here’s what I saw:
The text from “Dave Taylor says:” to the bottom of the page was all deleted from the file, then the file was saved to disk. Theoretically it should have vanished, but it’s still there and I was able to recover it.
How To Add Text Boxes In Google Docs
Hopefully this will get you back your missing prose!