Just reinstall the app with sideloadly as you would normally, without login out or deleting the old app and thats it.
I've done it a lot and everything works fine, no data lost. Also, log into game center so you progress is saved for when you're going to play the normal game. That one creates a different app, but any of these mods install replacing the one before, dont worry about that.
Also, what I do when I want to play in the regular app is installing the normal game in another iDevice, log with game center and see where the last save was, if its not where I want to, I just continue playing on the hacked one for a week. Just opening the game, maybe dating and nothing more (not spending anything) and about in the third day or so i have my full progress saved in game center and can enjoy the game the regular way but with all of my hacked things.
Sorry for the long reply, it's early here haha