This comes up fairly often on tinnitus fora. Basically there is some "consensus" that a shot of steroids within a very short window, ideally less than 24 hours, can help. Unfortunately, the most common response to damaging one's hearing seems to be to sleep it off for a week and hope it gets better, making it difficult to conduct a study on early responses.

There are studies though, and my conclusion is that it's still mostly inconclusive. Still, if my tinnitus suddenly worsened id be down at the doctor's begging for the steroids.