WTF Red legs (Colorblind)

Sorry to be the 1,000th post on here about red leg disease in a whites tree frog. But I've gotta post this due to me being colorblind and not wanting my frog to die just because my eyes are stupid. Just got this guy from a lady selling him, had him for two days. He seems darker overall to the two females that are with him, but I'm not sure if this belly is too dark and I need to get him to a vet. Much thanks to any info about it while he's in quarantine.

First photo is whout direct lighting, Third photo is with a light shinning on him.