for people who love the littlest dairy goats
I have not run into this but my first guess would be an infection. Have you taken her temp? Hopefully someone who has dealt with this will jump in.
Sounds like a precocious udder. It's more common in standard size dairy goats. I've never had it in a ND, but I did have it in a LaMancha one time. It's not a big deal. Just leave it alone, and it will probably go away. If you start milking, you may have to continue milking. There is someone on here that's been milking a precocious milker for years.