Please throw me a bone here...I did something like this last night and ended up having to reinstall 16.04 because I completely hosed Unity/Compiz.
I was messing with some hotkeys in the Window Spread tab of Unity Tweak Tool, clicked "Restore Defaults" and my panel & launcher disappeared again. I'm literally not logging out or anything until they reappear on my screen again, so I don't have to lose everything again.
What can I do to fix this that doesn't involve logging out and trashing my install? At least for now I can leave the computer on forever, and just use terminal to open things.
Here's an identical situation. Looks like the last guy was forced to reinstall as well all because he clicked one seemingly innocent button: http://ubuntuforums.org/showthread.php?t=2313458