The Romans located and cleaned up the site, then tried to hunt down Arminius; kicked his ass (it was close for a while), he ran off out of reach, and about eight years later was killed by one of his relatives (close family I guess). The Romans reoccupied what they’d lost, and added to it. It’s a common misconception that the Romans never recovered from it. What they didn’t recover from in the long run was the depletion of the Gallic population in the aftermath of Julius Caesar’s victory in the Gallic Wars. There had been a continual push westward down the steppe (a push that earlier on had got the Celts into western Europe in the first place) and that continued, getting worse as the climate cooled off.
There’s always something left behind.
I found this website which has a lot of archeological evidence in the way of relics found and maps which conform to Roman descriptions.
http://www.livius.org/te-tg/teutoburg/teutoburg04.html#Archaeological
I’ve always wondered what happened to the Eagles. Apparently they were eventually recovered by the Romans after some years. (same website, different page)