Help! Prezi auto-saved after I made an error and I cannot Undo my mistake (on a final project for my team)!

After pressing "Add" instead of edit to create a new "slide", I somehow changed the size and location of all my other slides in the vicinity. If there is any way someone can revert to a previous version of my presentation, I would be SO grateful (and this would save me from changing 40+ slides). I'm willing to take the hit on tonight's efforts so long as slide #7 (that affects the next 45 or so) is back in the correct spot.

http://prezi.com/4zstqfh9zlcs/great-b...

Please help!

-Shannon