Thank you for the photo.
You may want to trim some of the feathers away from the wound and the exposed tissue. This will make it easier for you to treat and it may stay a little cleaner.
Is she pooping at all - is any waste leaking out or none?
She's swollen, so the tissue likely will not go in. Keep that exposed tissue moist with an ointment. You can use neosporin, prep h, honey, vaseline - whatever you have on hand to keep it from drying out. You surely don't want it to dry and become necrotic.
You've done a good job cleaning her up. You may find more maggots tomorrow as well. That can happen. You read
@cherrynberry thread among others, so just do the best you can with this.
Hopefully she can pull through this. Having a prolapse is going to be a little more difficult, but just keep working her.
I would also get her hydrated, if she's drinking on her own that's great. If not, then add a little sugar to her water to entice her to drink. I would also get some Calcium into her. You can give a TUMS or Caltrate - 1 per day. This can help with retention of prolapse.
Keep us posted on how she's doing.