Marks on 2 year old’s neck

Kay

Hey just wondering if anyone might know what these marks could be on the back of my daughter’s neck.

I’ve always kind of noticed them but they were a super light pink, I figured it could be due to her sleep sack or maybe tags rubbing her back. Today it looks like it’s gotten worse though and that she might be itching it, due to redness I’ve noticed around it. Thoughts?