The further along they get the bigger the nipples should get. If you are concerned about her, you should call the vet and talk to them about it, as they are professionals, and can best tell you what is going to happen to her and the pups. Hope this helps you out, and best of luck to you and the mom and pups.
Two days ago my 3 year old boxer female.was licking her belly. When I looked there was huge red blotch and one of her teets was swollen. It looks like she may have been bitten by something. Shes acting as if the area itches, now its getting more swollen and she sucks in her sides when put your hands near the area.
This is how you spell vagina, and start your question out with the word "do" not does.