You are seeing a hairy nevus (photo)
https://healthell.blogspot.com/2021/08/you-are-seeing-hairy-nevus-photo.html
This is a hairy nevus, a growth like a benign tumor that happens to grow hair. This will remain unless it is removed. As this is a young girl, timing for removal is critical on a social acceptance level.
from BaldingBlog - Hair Loss Info https://ift.tt/3jtoDFg