African bull frog has pink/red belly by rear legs

[Kyles frog]

I have a bullfrog approximately 11 months old eats crickets, super worms, wax worms, and meal worms dusted a few times a week it’s tank is about 80 degrees and kept at a good humidity sprayed daily. I noticed earlier today it was molting I took it out of the tank and it belly was quite pink maybe even red some would say. Half hour or so after I took a picture and it wasn’t nearly as bad still took a picture though. What could this be? Rubbing lots from peeling off skin? Anything I should worry about? Thanks people!