Welcome to healthcare magic.
Your daughter seems to have Acute urticaria
. It is a type of allergic rash
with transient itchy wheals or nettle rash which changes location. Severe urticaria can cause swelling of lips and eyelids as well which we call angioedema
which thankfully is not there in your daughter. There are a lot of triggers for urticaria, most common is Food. Certain food like sea food, meat, egg, poultry etc are associated with more incidence but any food can cause urticaria and it varies from person to person. In kids infections (cold and cough, fever) are a common cause. Medicines, insect bite, intestinal worms etc can also cause wheals. You can give her an antihistamine syrup like cetrizine 5mg once a day and calamine lotion to apply. If it is not coming down show her to a dermatologist
Hope this helped