My frog has blisters?

[mike key]

I'm new to your frog forum so if I posted somewhere I shouldn't I'm sorry. I'm panicking I just seen our frogs has something wrong and cant eat. Looks like big blisters on there mouth. I have four frogs in the same 30 gal tank. My two oldest frogs (four years old) are the ones with this problem. They can open there mouth and eat. Please help me save my frogs. I found all my frogs at work they come in on plants mostly from Oregon.