@Unswydd how is your pullet?
She's in crisis. This is not just a prolapse, this is a prolapse with stuck egg.
You may be able to save her and work the egg from the prolapsed tissue or not.
She needs to be brought inside where you can work on her and kept somewhere that flies can't get on the exposed tissue nor other chickens peck at her.
Can you find the opening where the egg is supposed to come out?
It's extremely important that you try to get the egg out and that the tissue does not dry out. You can use just about any type of lubricant that will help the tissue stay moist - vaseline, coconut oil, prep H, organic honey, anti-inflammatory cream, etc.
WATCH the video below. Tums can help after you get the egg out, but it needs to come out.
If you need to, get some more clear well-lit photos and post them, I'll see if I can help find you find the opening.