You can read about mange mites and ivermectin on Guinea Lynx (click button above).
I must say, I would be tempted to try to do something for her. Perhaps someone more experienced could offer their own advice.
On a positive note, they don´t have a warning against using it on calves or baby pigs on the handout that comes with the Ivomec injection -- but they only mention cattle, pregnant and older animals, so the very young are ignored.
If it were my animal, I would probably treat it, but I don´t feel like giving unqualified advice to others to do the same.