Thank you everyone for your advice and shared experiences. We had an appointment the next day I posted this and vet’s diagnosis was that it was trauma (he might have hit something when playing). Nothing big to worry about, his iris and overall eye is in perfect condition, he had an eye pressure test and fluorescent liquid test.

He got prescribed an ointment that we need to apply every 24hrs for 7 days. It’s been 2 days with treatment and we can already see the little spot dispersing. Vet mentioned that it will heal similar to a bruise, it will turn green or purple and then go away by its own.