Oh yeah, that is a good point, DVirginiana. Perhaps it was related to shedding. I have heard some awful stories...

What is your humidity at? If the humidity is too low (below 60%), then your Pacman Frog could have been injured while shedding. I have heard stories (plural) of frogs loosing limbs during shedding, usually because the humidity was too low. It makes a big difference to Pacman Frogs.