Help! New to African Dwarf Frogs and one is sick!

[Dflick2012]

I am new to owning African dwarf frogs. I got two about a month ago. A week or so into owning them they both shed. I noticed the one had a white bit on his nose after he shed, but I assumed it was leftover bit of shed that still had to come off. I own bearded dragons and that is normal for them to have a piece of shed to come off later than the rest.

It has has since progressed and now it looks like his mough/nose are rotting off. I have quarantined the sick frog and changed the water for the other frog. I have the sick frog in bacterial/fungus medicine.

Has as anyone seen this before?
what is it?
am I doing the right thing?