Cc sliders?

I am assuming that you downloaded the toddler neck slider by Redhead Sims (it would really help if you could be specific as to what mod you are using if you want us to troubleshoot). To use this Mod open edit detail mode, turn the toddler sideways, then wave the curser over the edge of the toddler's eyebrow and the neck width will change.

See the third picture down to see what I mean:
https://redheadsims-cc.blogspot.com/2018/08/toddler-sliders-presets-height.html