I had similar experience, though not the prompt treatment with steroid.
Please make sure you have good ear protection for the MRI. Exposure to continuous loud noises of the machine will very likely make your sound sensitivities MUCH worse. That is what happened to me. I was rushed into the MRI machine with ill fitting ear plugs. I did not understand that I should STOP the proceedings until my ears were well protected.
Good luck. I have been in a similar situation for two years now. Still deteriorating hearing and profound sound sensitivity and tinnitus.