Ok, thanks so much!
What would signs of an infection be? And would it be OK to put some Stress Coat in his water to help him heal, or should I just leave it be?
If you notice white fuzz or slime he probably has a bacterial or fungal infection. Other than that, I don't think there's much to look for.
Oh, and no, I wouldn't add Stress Coat. I'm not the biggest fan of the product but for frogs I don't think it even does anything (besides de-chlorinating tap water which is the only thing it should be used for IMO).
As long as the water quality is good he'll probably be fine so don't worry too much

. Especially since he's acting normal otherwise.