Help? Bumps all over

What could this be? Started with bumps all over face and neck with a rash and just a few on her leg. Peds said it was heat rash on upper body which she does sweat bad in the car seat she always warm regardless. But she said the bumps on the leg may be a start of a contact allergy or food allergy Im EP.. trying to start now cutting out dairy to see if it’s that but I been haven dairy so I feel like it ain’t that?

Well we decided to quit the vitamin d jsut to see cause that’s the only thing because we started that two days before this happen just to see..the face cleared up tremendously dont know if it’s ironic or that caused it? We use the all free degernt and dove baby soap..But now the bumps on her legs is increasing and on her arms and some in her head/scalp as well but nowhere else? Pics below

Waiting on pediatrician to call me back was suppose to Friday🙄

The start of her face and neck ear was really bad at one point!

What it looks like now definitely going away..

But now the arm

This is the worst spot on her arms they are kinda scattered on other limbs