Restoring deleted cache

Is there a way to restore deleted OneNote caches? As OneNote (2016 client) kept freezing I clicked the offered option to delete the cache, which resulted in all notebooks being taken away. Since the notebook I had been working on (offline!) had not synced yet this is disastrous. Anyone knows a way to put back the deleted cache? Or is it completely lost? I haven't turned the laptop off yet, so I'll leave it on for now It's on a Samsung 500T 2in1 that is getting memory space issues. Don't you just love Windows for that :S

Thanks in advance for any advice!
Regards, Erwin