What you need to do if you find a ringing in the ear after a night out or suspected ear damage is to let the ears rest from any noise. Put a pair of plugs in and relax. Don't listen to any music and avoid metal to metal noises. The best is if you can find a proper pair of earprotectors (cup style) and wear them all day long. Sleep more than usually and eat a lot of proteins. Don't clean out the earwax either as it helps dampen sharp noises.
/LnS