Thanks for your query.
Swelling behind the ear are lymphnodes
which get enlarged due to infection.and they decrease in size once infection gets settled.
You can continue with acetaminophen
if temperature is above 100F.
lotion over lesions and if there ia itching you can give antihistamines for symptomatic relief.
Give plenty of fluids and soft bland diet to maintain hydration and nutrition.
In case symptoms persist get her evaluated by pediatrician
Wishing your child good health.