I avoid most medications, especially without a diagnoses, and on any amphibians (plus shrimp, labyrinth-organ fishies, etc) mainly because it can do more harm than good.
What objects do you have in the tank? An overcrowded tank, can have the frog more skittish (during the night especially) and slam into objects, or him moving around the sharp edged interior of some decorations can cause wounds.
A fungal infection there would be other signs; lethargy, discolouration, a fluffy look to the fungus, and sometimes a decreased appetite.
Though you did not have a secondary tank to quarantine, I would recommend next time not getting another fish or water critter until you had a quarantine available. Though it can be tempting to get more, or something like an ADF, it can endanger your entire tank if that one addition has diseases such as fungal diseases, or even ich (which attacks weakened hosts). Columnaris I found in my area is the top problem for people new to aquariums, which usually wipes out most if not all of their critters in their tank if not caught right away - or prevented.
If you have something as simple as a gallon bowl, drum, bucket, or other container 1+ gallons he can be placed in there. I added live plants for the frog's quarantine when I had an ADF, and since they do breathe from the air it is not imperative to have a filter or bubbler, but you could hook one up for an extra measure. Clean, warm water is the best bet right now, and check on your fish often. I check during feeding times... Count the fish, check them over, feed them, watch their behavior. I've learned my fish individually to know when they are feeling "blah".
If he needs medications, I recommend removing him. No need to send the other fish through the same thing if they have not caught it. It could still be as simple as a wound, his body's natural defense trying to fend off infection.
Breed for the breed, not for the money; the words any REAL breeder would understand.
You must know nothing in order to know all, for all is nothing and nothing is for all.