It's a very serious thing and it's dead simple to produce dangerous loudnesses, that close to the eardrum. What I ended up doing for tracking drums and loud things, is investing in some heavy isolation headphones, Sony drivers in the same kind of heavy tight enclosures used for ear protection at gun ranges. They're pricey, but they work.

Otherwise, you're still getting close to the sound pressure levels of whatever drums or amps you're playing, and then you're trying to turn up the backing tracks in your headphones to be enough louder than that, so you can hear what you're working on. And that's super dangerous.

Same thing with music to drown out noisy subway rides or what have you. You'll go deaf. Extra fast.