If you'd made a change you're not satisfied with, the Versions button you to "roll back" your changes to a previous copy of the page.


Clicking the versions button will present a list of all previous versions of the page. 
You can preview an older version by clicking its name.
The bold line in versions is the version the general public will see at this URL.
The top version in the list is what you're editing as an admin.
You can check two versions and hit compare to see any copy changes highlighted. 
To roll back to an earlier version, simply check the desired version's checkbox and then click the Approve button. When exiting edit mode you have the option to change the comments for the version to allow you to more easily identify that version.