OMG that looks NASTY! Hopefully you are either at the vet now or have already been there!
I'm curious, how long did it take to get to this point? I guess I'm just curious how long it takes scale rot to develop.
I make it a point to check my BP over each and every time I get her out of the tank which may only be once every few days. If this kind of problem can occur quickly, would it be wise to take them out more often?
I wish you the best with your BP! I hope the vet can treat it. It hurts ME to see that! OUCH!