Hi.
If the ringing is persistent, it doesn't actually have to do with the hairs most of the time. That's Tinnitus, which is very common. Nobody knows what causes it but it as it generally happens in the inner ear. There is a very brief ringing that occurs when the hairs die, but it's usually very short.
Some medications can actually cause hearing loss after prolonged and frequent usage. Ibuprofen, for example, is a particularly common one that most people don't know about. (I think they call them Ototoxic medications.)
Here's a pretty verbose list of drugs that are considered ototoxic.
It could be the sign of something more serious too, you should talk to your General Practitioner or an Audiologist.
