Bag balm is a salve that is used by farmers to keep cows' teats from getting cracked and dry in the cold months.
You can usually find it in a pharmacy. For some reason it's usually kept behind where they keep meds, but it's an over-the-counter item. I think it's under $10.
Go down the PS for another very good use for bag balm.
HOWEVER, I really think you should take her to a vet. I do not believe in trying to diagnose over the internet, and as far as I know, we are not vets.
You're not just dealng with her now, you have the babies, and what if you try the neosporin, it doesn't work, and what she has it catching and the kittens get it? Then you've got real trouble.
Plus, it's in a place where the kittens nurse and mush their heads and mouths, you want them ingesting that stuff?
Please see the vet.
PS: Bag balm is fabulous for your skin. Before you go to bed, wet your face with warm water (don't dry it) and put bag balm over it (as if you were using face lotion. When you wake up and wash it off, you'll be amazed at how soft your skin is. Just know that it is very greasy, so cover your pillow with a towel or a very old cruddy pillowcase so you won't ruin your good things.
I found this out from a TV show about women who looked much younger than their years. The woman who told about it was 72, looked fantastic, and she was told to use it by her husband, who was a dermatologist.
It's also great for things like cracked heels...wet, cover in bag balm, and put an old sock over it before going to sleep.