there is no option to go back under Settings > Update & security > RecoveryDo you also have the $windows.~bt folder?
"Settings > Update & security > Recovery. This will keep your personal files, but it'll remove apps and drivers installed after the upgrade, as well as any changes you made to settings.
To go back, you'll need to:
Keep everything in the windows.old and $windows.~bt folders after the upgrade.
Remove any user accounts you added after the upgrade.
Know the password you used to sign in to Windows 7 or Windows 8.1 (if you used one)."