Welcome back to Healthcare Magic Physician's Desk!
It seems you have got some tiny insect or some chemical exposure in the affected eye.
Wash the eye liberally with tap water with eyes open to decontaminate it.
Take tablet Levocetirizine
5mg for three days, start as soon as possible.
Instill eye drops Moxif
one drop thrice a day.
Wish you a great health!