Hello alinadeal,
Thank you for reaching out in Apple Support Communities. If the notes were already saved, then the option to revert back to its previous state is unavailable. You may need to redo your notes again. Another option is if the notes were not synced to iCloud, you might be able to restore a backup of how the notes were initially. You can see if there's a recent backup available and restore your information.
Here's how to locate a recent backup: Locate backups of your iPhone, iPad, and iPod touch - Apple Support and if there is a backup in which you can restore your notes to how it was, you can follow these steps to restore your data: Restore your iPhone, iPad, or iPod touch from a backup - Apple Support
Kind regards.