Answer:
Unfortunately damage to the ear drum is not reversible. The best thing to do is avoid exposing yourself to excessive, loud noises. Hearing loss is not a normal part of aging as people get old, it is ONLY caused by loud noises. So prevent yourself from developing hearing loss, prevention is all you can really do.
1) I think you've already answered your own question, you just need to listen to yourself sooner and more closely. 2) If something is causing you PAIN, it's clearly time to quit doing it, in fact, in this case, it's way past time. As far as "What can I do?" is concerned: Again you already know the answer, and may I suggest you listen to your wise self and never put you or your ears in a position to be hurt like this again? Hearing loss is permanent and to my knowledge, unfixable. Is heavy bass really worth being permanently disabled? I could go on and on and continue to sound like yer ma, but I'll spare you and me the agony. Don't do that again, you bad boy/girl...