Poor girl. Another warm soak then rest in a darkened place might be the way to go now. Maybe some Neosporin on that red bottom, for comfort if nothing else. Hopefully, some time in a darkened place will relax her so she can pass whatever is up there, and maybe send a signal not to lay another one for a while.
I'm no expert at all on this. There are lots of threads on here about eggbound. Have you checked out these two from the FAQ page? I see some different methods mentioned.
Egg bound
https://www.backyardchickens.com/forum/viewtopic.php?id=32648&p=1
https://www.backyardchickens.com/forum/viewtopic.php?id=22308
I'm no expert at all on this. There are lots of threads on here about eggbound. Have you checked out these two from the FAQ page? I see some different methods mentioned.
Egg bound
https://www.backyardchickens.com/forum/viewtopic.php?id=32648&p=1
https://www.backyardchickens.com/forum/viewtopic.php?id=22308