Thank you for your query,
It seems to be a viral exanthematous fever
Yo can give paracetamol
syrup in prescribed dosage every 8 th or 6 th hourly depending on the presence of fever and headache.
If there is high grade fever, to tepid sponging of the whole body.
Try to give plenty of oral fluids, juices, and ORS
Consult your Pediatrcian for the examination of your child and for specific treatment.
Hope I have answered your query.