Good to hear that the ear builds tolerance after a while.
I guess I will need at least another year to do anything remotely like that. (Not that I'll ever not use earplugs)
Since I already had a spike after 3 hours max 75 dB.
Providing you do not overuse ear protection, your auditory system should return to normal as before with time. However, this doesn't mean using headphones even at low volume and deliberately exposing yourself to high sound levels. I have no sign of hyperacusis even though I had a second noise trauma in 2008. It took 4 years to habituate for the second time.
Michael