Why Didnt My Products Restore Using My Backup?

I ran a price update by uploading a CSV file to upload products. All of the products were under “Ducati OEM Parts Category”. We restored the site to before the price update because we wanted to change the product descriptions as well. Now most of my Ducati parts are gone. How is this though when the Ducati parts weren't in the “Ducati OEM Parts” category. The parts that are missing are under other categories like “Ducati 1199 Panigale” blah blah blah. So after this, we restored way back to December 12, 2013's database to see if those products would come back. They didn't. The products are still gone. Shouldn't the products be there or are they permanently gone?