Please note that I am not a vet, but it looks like a cut got infected. If it is hard to the touch it is most likely a tumor. If it is soft it is most likely an infection.
I'm not sure. I let it go again, since it was a wild toad, and I figured i couldn't really do anything for it. Besides, look at it. I would never touch that thing!
I'm thinking it was an infection, since in the picture it looks like it has gook coming out. IDK, hopefully I didn't cause it pain. I tried to not touch the red thing, and I definitely tried not to grab the toad too hard. I feel bad for the poor thing.