Matt had a major concussion. As for the tinnitus, yeah, that should've lasted up 'til at least the end of "New York's Finest" since the rooftop scene immediately followed the failed police sting. He was fine by "Penny and Dime," although from the looks of it, that may be because there's a couple days' time skip during which Matt could've recuperated and taken medication (based on the interaction when Karen helps him with his tie).