Does it sort of look almost like stretch marks inthe way it's appeared on your skin? I mean, sort of like you can see that the kskin has stretched and those lines are red and itchy?
Is it very dry and very cold where you live?
I get this on my breasts and calves in very cold weather when I've not been hydrated/lotioned/covered well enough, even long before BFing. So when it appeared while BFing this winter, I've been drinking lots of water, running two humidifiers in the house 24/7, wearing mostly cotton clothing, limiting my shower length and keeping the temp of the water cooler than I'm used to, lotioning up a lot, and using lanolin (Lansinoh) on the breast skin that is irritated. It seems to be helping quite a bit.
Also, rubbing some expressed breast milk on it a couple times a day seems to really help the redness.