Total noob - some kind of morphing made my drawing disappear

Hello,

I was playing around (while having the auto save on) and accidentally did something wrong (which got saved). I don’t really know what I did because I was just planning to discard of any changes by closing the program when I was done playing. But as I said, the auto save had saved over the file during that time.

I think I activated some sort of morphing because I wanted to see what would happen, and my drawing layer disappeared. My timeline has arrows on it and it says “morphed drawing” when I hover over it.
If I right click on the first frame and go under morphing I can’t seem to delete it (or create, for that matter).

If I click on morphing in the left toolbar I can see that my upper lip drawing which has disappeared is the only one that says “main” in the morphing tools option. I don’t know what any of this means, I just want my drawing back :’(

Does anyone know how to fix it?

Thanks in advance

EDIT:
Here are the files if anyone wants to have a look. His lower lip is the drawing that’s disappeared.

harmony morphing tool options.jpg