problem ears dont feel right

My 4 yr old son has had constant issues with his ears and hearing and after getting grommets at the beginning of this year he was wonderful for a little while, his behavior settled, speech improved and overall we deemed it to be a success
just a few months later though he was slowly but surely heading back to his full on old self and even toilet training is going backwards
He has been back to the ENT once who claimed that there was still hearing loss as his ears were blocked but basically just sent us off with a "theyll sort themselves out"
Since then he has had a possible perforated eardrum, severe ear infection and more than 1 doctor tell me the grommets are in but his eardrums dont look like they are healthy or working
we have been put back in for a hearing test and we are getting the next couple of weeks but what im wondering is has anyone had issues like this and it ended up being a misdiagnosis?