How to backup individual page in sharepoint

1. Open the site in sharepoint designer and select(or (highlight) the page you want to backup.
2. Goto File -> Save As and save it to your local desktop.
       or
   Click on the "Export File" option from the ribbon and save it to your local desktop.
3- Copy the file which you saved in the desktop.
4- Go to your production, open your site collection in the sharepoint designer.
5- Go to site pages -> Paste the file which you copied.
   Sharepoint designer automatically saved the page in the database.
6- Open the page using browser by navigating your site.