4 year old noise in ear

[Kel33]

My 4 year old has been on antibiotics for suspected ear/sinus infection last week and finished the course on Monday this week. He has definitely been struggling with his hearing the last couple of weeks. The last couple of days he has said he has a 'noise in his head' or his ear. He says it comes and goes but makes it hard for him too hear. He seems to think it's just one ear when I ask him to show me.
He does have enlarged tonsils which he is under ENT for but rarely suffers from throat infections etc.

I'd just saline squirted up the nose twice a day. As it's coincided with the infection then it's probably just residual fluid build up.

I’d be asking them to look in his ear. Could be a wax build up, or pressure from inside the ear drum.

Did they give him oral antibiotics? If so I would go back and get them to look again. My child was under ENT for years for ear problems and orals never worked. She had to have the ear drops

This sounds like tinnitus which is a common side effect even from a mild ear infection. It should improve of its own accord but ask to be seen by ENT for review