Before downgrading from iOS 11 to iOS 10.3.2 i made a mistake. How can I fix that?

I downgraded my iPhone 6 from iOS 11 Developer Beta 1 to iOS 10.3.2 and I made an iTunes backup before downgrading, and i didn't have iCloud enabled, so all my files are stuck in the iTunes Backup. Is there a way to get back all my stuff?

Restore to THAT backup and start your process over.