My money would be on this NOT being an ear infection..........and anyway this has only been going on for a matter of hours and he has no temperature and eating normally.
It is often confusing for an inexperienced GP as when a child is screaming or crying, the eardrums are red, mimicking an ear infection.
What would I do?....Nothing.......give him Calpol at night and monitor the situation, but if he goes off his food, starts a temperature, then take him to your GP.
No big deal at the moment................and probably never will be.