I removed wallpaper and removed the top layer off the drywall. Can I repair this?
Yes, this can be repaired. First, seal the damaged walls with Kilz or equivalent primer. This will keep everything together. If any paper bubbles after priming it will need removal before proceeding.
Now all of the damaged areas can be floated over with drywall mud. Most likely it will take 2 or more coats. Allow the final coat to dry, sand smooth then prime again before painting. A texture can also be added after the final coat of drywall mud.