Wow she's having a tough day, since the color of the protrusion is more of a red-ish color, the leading suspect would still be camallanus.
A prolapsed anus is also difficult to treat as there can be several causes. It either heals or it does not. It can be a sign of blockage, which would eventually be fatal.
Recommended treatment (for prolapsed anus) would be:
1. Stop feeding for a couple of days.
2. Dose with Epsom salt at 1 teaspoon per 5 gallons.
3. I'd also dose with API General Cure (or another medication containing metronidazole & praziquantel).
I'd try the up one method or euthanize the fish, to prevent any suffering. I'd also recommend not allowing her to give birth again if she pulls through, if she prolapsed now she will be more prone to this in the future potentially causing further damage.