If the prolapse pushes back in , sometimes the cream you use for human piles , can help. It encourages everything to shrink back in and hold in place or another thing that the vet advises as 1st aid is to use sugar water on the prolapse after you have cleaned the area , as that also causes shrinkage.
Advice sometimes is given to dietary change as the layer pellets will keep encouraging her to lay and ideally you want her to have a time off lay for everything to settle and firm up.
I have taken 2 hens to the vet to get a purse stitch put in to hold everything in place and for a short time it worked but in the case of both hens they did prolapse again after a couple of months. Tough sometimes isn't it ?