She has a sensitive skin. It is response of the body of some peoples with sensitive skin that any thing when struck or when they scratch hard, cause patches or some time keloids. Doctor is right, don't worry.
My Childs Doctor Said That A Few Petechiae Spots On Here Was Common, She Has Eczema And Sensitive Skin, Is That Normal For Her To Get Some Petechiae Spots From Scratching Too Hard?
This is likely very normal. I also have sensitive skin and get these spots all the time from scratching an itch too hard. They usually disappear after a few days :)