By making use of revision control that comes built in with Drupal 7, you can revert back to previous versions of your content.
To create a new version of your content, click on “Revision Information” that will be visible on the bottom of the content when you are editing the specific content.
Then, click on the checkbox that reads “Create new revision” and add a message in the input provided to describe why you are creating a new revision of the content. Then save your content.
This will create a new revision of your content and will direct you to the revisions page, looking similar to the example below. You can use this table to revert back to any previous revision of your content by click on the text that reads “revert” on the row containing the specific revision. You can also view the revision by click on the name or title of the specific revision.
You will also see the new “Revisions” tab on the top right. You can click on the tab to access this page on any content that has revisions.