My son is 4, he had an ear infection over the summer that seemed never ending. Because they could not see his ear drum they had me come back for a check after the antibiotics. His ear drum must have ruptured at one point because blood came out of his ear. They flushed out his ear, got a bunch of gunk out of it and after that he said "Wow, I can hear again!" It turned out that on top of an infection he had a ton of wax, which helped keep the infection growing too. But a word of caution, he got another one soon after and they gave him ear drops, which eventually led to a fungal infection. I'd go back to the pedi once the course of antibiotics are done if he'd not hearing better. If they seem unsure of why he's still having trouble, I'd ask then to recommend an ENT.