Revert changes to picture?

[LifeIsLong]

I selected a bunch of photos and dragged them, then dropped them in the same folder. The effect of this is that all of the selected pictures not have all of labels from the entire selection. Each photo now has 26 labels. I have not saved the metadata yet, is there a way to revert this change? I tried reading the data from the file, but this did nothing (that I can see).

[LifeIsLong]

So in dragging/dropping, I created a version set of 118 pictures. Which is why they all have 26 labels. Is there a way to revert? I know I can destroy the version set, but this wont reset the labels...