Agreed. It's pretty solid that it's one of the two. I'll start by preparing a quarantine tank tomorrow, and since I'm getting new substrate tomorrow as well, I'll clean out his old tank entirely. I'll quarantine his tankmate too, I think. And I'll definitely clean out anything used to clean their tanks as well as contents.
My theory is that since I've never treated either of my Chorus frogs for parasites, the short tongue syndrome developed during my vacation, caused stress, and caused either the parasites to take advantage and infest the frogs or an infection to occur. Or both.
Really bad timing for all of this too, because it's my birthday tomorrowand I just got back to school. But, you do what you gotta do.