I had sever nipple pain in my second pregnancy. It was quite sever. I am very glad to not have it this time.
Anyway, I was told it was likely due to something called Raynaud's syndrome, and that it was probably a pregnancy thing that would disappear after baby was born.
What helped was keeping my breasts very warm. I wore a fleece tank top under my clothes to help with this. And if the pain was very bad, I used very warm compresses or rice socks I had heated in the microwave. That was the only relief I could get. The warmth dialates the vessels allowing for free blood flow. In Raynaud's syndrome blood is constricted for whatever reason, which causes the pain. If your daughter can find relief from warming her breasts, than it is likely her nipple pain is from the same cause as mine was, I would think.
The good news that you can tell your daughter is that the pain WAS pregnancy related and completely disappeared after the birth of my baby. Now, if she has never breastfed before, then she will find that breastfeeding can be a little painful in the beginning as mother learns how to latch baby on properly, but it is short lived, and has nothing to do with the nipple pain she is experiencing now. It may be good to make sure there will be a lactation counselor available to her after the birth of her baby to help her learn how to latch the baby well from the start. That might help her feel a little more confident that she is making steps to minimize pain and discomfort. But again, the sever pain she has now is likely going to vanish with the birth of her baby.
Kim. My heart is full! Wife to Ray, Mama to 3 boys! "Big C", our boy with designer genes, "Little C", and "Baby M" 11/2010.