it sounds like it may be "tinnitus," a condition that I myself suffer from. And one of the leading causes of it is exposure to loud music. I got it from a mixture of that and a drug experience in college (they've showed a weak link between tinnitus and taking ecstasy based on testimony from people). Anyway, the bad thing is that there is no real cure for it...certain herbal remedies are available - to what avail, I'm not sure. Turning down loud music and other similar situations are the best advice that I got from my doctors. I've had it for over two years. There is a little optimism in it: my doctor says it tends to disappear after some years.
ps. using things like electrical fans, etc. helps to drown out the ringing while sleeping, or tune a radio station to an AM station that just gets static to see if that helps.
Hopefully though, you don't have it. Just give it some time - no discos for a while.