Well, ya don't have to say "sorry" to me

I'm patient when I'm not flying. I won't be upset if it never gets done, just trying to be helpful to another skinner.
Several times I've accidentally hit CTRL-S and saved a flattened image over a layered one. The best thing to do is to show your history window, and click above the "flatten image" event, then save again.
If you did it a while back the only thing for it is to scroll all the way to the top of the history and click the "open" event -- you lose all the work this session but the file reverts to where it was before (it has layers again).
Also this is a good reason for saving iterations. I'll start on panel lines first, and outlining general areas. When working on these I'll save as xxxxx-1. After this I'll start saving -2 -3 etc when I make major changes or major progress to the camouflage. Sometimes I go back and change camouflage, but don't want to lose the previous work I've done. That's a new version. If I don't like it I can go back to the old file and copy the layers into the current file.
If I decide the colors are off I'll add a sub-version. I'll change the colors but name it, for example, 109e-4_5a instead of 109e-4_6. That's if the change is only minor.
Definitely takes some effort to discipline your saving habits. I lost a lot of work on my early skins until I re-trained myself how to save files.