My 5 year old has developed these spots, she has had these for just over a month

My 5 year old has developed these spots, she has had these for just over a month. She had Scarlett Fever which was treated and cleared up, about a week later she had one large spot appear that looked like chicken pox, it turned yellow then burst and went red, more then started to appear.
It’s mainly down one side of her torso, but a few smaller ones are on her arms.
Our GP initially thought chicken pox, the shingles but now doesn’t know what it is.
How can I treat it and stop it spreading.