Do not be alarmed if it comes back out again. It can easily take several tries before it stays put.
As noted above, keep her in a dark or dimly lit comfy quiet stress-free area for the next few days (e.g. a small bathroom that can be an infirmary or a large dog crate). She will hate it but it will slow down egg production so she can heal. If she has a good buddy, you can put her buddy in with her. Just make sure the buddy is not pecking at her bum if the prolaps happens again - they will have to be carefully monitored. With this in mind, maybe you could just have the buddy visit for short periods when you can keep an eye on things.
Ply her with some treats to keep her spirits up during this time - sunflower seeds, scrambled egg, little cut up pieces of fruit, yogurt, oatmeal, along with her regular food of course. If you have Avia Charge 2000, have a bit in her water for extra nutrition.
You are doing a good job!
JJ
Edited to add that I just saw we have a vet in 'residence'. That is fantabulous - thanks songbird!