dragging and dropping all my folders into the hard drive folder I made in lightroom
First- How did you drag and drop? Did you use Lightroom in the folders panel, or the Operating system?
If by OS, then you have moved all the folders with images to their new location and the database link in Lightroom is still looking for the image files in their 'old' location. Your images are not IN Lightroom!- ever!
Read carefully until you understand how the catalog makes reference to your image files-
Yes, I made a folder called backup in lightroom so lightroom would recognize the external hard drive. Then I dragged n dropped the photo folders into the folder called "backup" in lightroom. I did use lightroom in the folders panel. I wanted my photos to still be in lightroom just wanted them backed up on another drive. How can I get them back into lightroom?
All the photos now have ? in the corner also.
Your procedure to drag the folders in the LR folder panel has in fact MOVED them to the "Backup" folder.
They now reside on the external hard drive.
There is no backup anywhere. The folder you created called 'Backup' is now your working folder of images.
To edit or work with the images in LR you now need the external drive connected. If it is not connected LR will say your images are missing [!] and folders are missing [?].
Your method to back up should have been to simply use the operating system (or other software) to COPY all your image folders to the external drive. Nothing to do with LR for this. Your 'originals' should remain where they were before.
To correct your setup you should use the OS to COPY the folders back to their original location on the internal drive and update the location of the topmost parent folder of images.
But before you do, Read and understand-
I wanted my photos to still be in lightroom
Your photos are NEVER IN LIGHTROOM, they are where you put them on your hard-drives (internal or external). And dragging them in the LR folder panel moves (NOT copies) them to a new location.