This is BonBon, a possum who developed dermal septic necrosis due to stress and abrasions on her neck and chest.
Any possum who comes in with breaks in their skin is at risk of this system wide infection. Luckily, she only began to develop it after intake. It is sepsis that develops outwardly as well as internally and is identifiable by the dry necrosis that develops on extremities like their ears, nose, tail, and toes. This is what earned it the name 'crispy ear'.
It can also rarely present as wet necrosis, which I've personally seen develop as swelling on limbs that quickly develops into gaping wounds. By quickly, I mean only hours.
It must be treated immediately with antibiotics as to prevent the necrosis from spreading and their organs from shutting down.
Below are progression photos of her tail after intake. This occurred over 4 days, and while she was on antibiotics.
