Welcome to HCM,
It seems that your child is having viral infection.
Darolac-Z does not have this type of side effect.
Give him Syrup Benadryl
or other decongestant syrup.
He will feel relief within an hour.
Continue 2-3 times a day for 2-3 days.
You can put antibiotic or some decongestant eye drops.
Ok and bye.