Good advice to keep her separate inside a dog crate, but close to others so that reintroduction can be easier. Is she able to pass any droppings? Sometimes an egg can be stuck when a prolapse occurs. Do you feel anything lick an egg? Soak her in warm water daily to keep her clean and to help it heal. A little Epsom salts or Dawn can be used in the water. The black skin is necrotic, so hopefully that will fall off in days. Once dry, apply ointment to the prolapse to keep it from drying out more. It may take days to a week for the swollen tissue to go back inside. I would probably give her human calcium citrate with vitamin D 1 tablet today and tomorrow. That can help with muscle contraction, or help the prolapse.