As per complaints given by you, he has only fever and no other symptoms.
Kindly reduce the dose of P250 syrup to 3ml ONLY.
Moreever, rather than P250, you can give him SYP IBUGEAIC PLUS 6 ml every 6 hrly for next 2 days and after 2 days give only if theres a fever.
Inbetween, if fever is not controlled with IBUGESIC PLUS, you can give give SYP. MEFTAL P 5 ml.
Watch out for other symptoms.
Next Steps
If possible, do visit your pediatrician.