Thanks for the query.
This could be Chicken pox. However, the diagnosis can only be confirmed after a physical examination. Kindly consult a dermatologist at the earliest so that acyclovir can be started soon. You can give the child Paracetamol (dose as per weight) for fever. Adequate fluids and rest is advisable.
Next Steps
Your dermatologist will decide a treatment plan for you after a consultation.