welcome to hcm.
It is suggestive of a exanthematous fever
probably of viral etiology as per the description here. Kindly mention the age of the child and any allergic reactions in the past and any family members having the same issues or any allergies or any episodes of fever.
U can give Paracetamol
syp 10-15mg/kg body wt to ur son for fever and Cetrizine
syrup for the allergic reaction to come down and please take an expert opinion with the nearest Paediatrician with the the following tests done:Complete Blood Count
, Widal test
, Dengue IgG& IgM test, MP smear to rule out Malaria. and please follow up if the fever and other symptoms persists.
avoid any allergens if any and exposure to extremes of temperatures.