retrieve whatsapp local data

Hi guys, today I suddenly got signed out of whatsapp on my phone, I didn't reset or delete the app or anything, it just happened out of nowhere, I don't have an updated backup so I couldn't restore it from iCloud, however when I opened settings>storage> I can see that whatsapp has +700 mbs so where is it? how can I recover this data.

I don't want to back up the phone using itunes as I'm afraid it would overwrite this 700mbs with what I have now, no data in whatsapp.

please help