I really wish I knew what exactly caused it. It's definitely got to be something like rubbing against something, although I still lean towards it just was jumping into the walls. They had no backgrounds on it's tank where I got them, lots of foot traffic/tapping on the glass I'm sure. Definitely not a good mix!! hahahaa
But as far as treatment goes, I'm a big believer in trying to keep everything natural. I tend to stay away from nose rubs/meds unless I notice it gets worse. I've only had it happen maybe 3 times in my years of frog caring.
So I just trust my instincts and try to monitor the frog every chance I get. My "Amphibian Room" is very, very calm and peaceful. Tanks are always clean, so there was no worry of it getting infected. Made sure it ate the right foods, etc. Turned out to be such a great recovery too. Looks healthy as ever right now.