Oh, I see. I didn't know that was possible in Launchpad (haven't used it much). Just created a folder by dragging on app on top of another, and Launchpad dynamically/automatically created a new folder similar to how it happens in iOS. I kept the default name given to the folder (Utilities). Closed the folder, opened it, then dragged each app back out of the folder. There were just two apps. Soon as I dragged out the 2nd app, the Utilities folder automatically disappeared and my Launchpad and the apps were back as before prior to creating the Utilities folder per the process above.
So, if your folder is still there in Launchpad you could try to drag just one app that's not in a folder to the empty folder. Close the folder, open it, then drag the app back out. Maybe that will then automatically delete the folder?