The save screen took awhile one time for me...I ended up tapping the touchpad area a few times with my stylus and it finally move to the home screen...
But I wouldn't turn off power in case of corruption. So... :x waiting it out would prolly be best.
It's happened to me several times before, on my main town. I was using my old 3DS then, so I was able to switch off the wi-fi. I'd heard that helps, and it did! I don't know why, but it did.
If you're on a New 3DS, though (like I am now), I'm not sure if there is anything you can do but wait.
I know you posted some hours ago...how did it turn out?
^I guess shutting off your router could help when using a N3DS. After over a thousand hours and many many saves this has never happened to me but I’m glad now I know what to do if it ever does