Unfortunately you have done the damage.
Here is a diagram of the ear.
So sound travels along your auditory canal. Then it encounters the tympanic membrane which is the microphone diaphragm. This is connected to the three bones of the middle ear. This is an air containing cavity. The air reaches it from the nose, via the narrow gauge eustachian tubes.
The bones are constructed to exchange movement for force as the stapes impinges on cochlea which is fluid filled. Fluid is not compressible.
Now we take a look at the cochlea.
The sound waves are therefore converted completely to waves of pressure. These are received by the inner and outer hair cells connected to the Cells of Deiters.
This is an Analog to Digital converter. The digital pluses are then transmitted to the auditory cortex of the brain, for decoding via the auditory nerve, which is the eighth cranial nerve.
Now biological systems are chemo/electrical. The electrical pulses are created principally by fluxes of sodium, potassium and especially calcium ions across cell membranes.
Now the hair cells especially, and the auditory nerve to an extent are especially susceptible to noise induced damage. Once killed they are not replaced. As they die they produce these spurious high pitched noises known as tinnitus.
Once this process starts, it can not be reversed. So hearing loss becomes progressive, starting with the highest frequencies. Once hearing above 3K is lost understanding speech becomes progressively difficult. Once frequencies above 1.5 K are lost deafness becomes profound. At around the loss at 3K hearing aids are required.
Once deafness becomes so profound that it beyond the help of hearing aids, the only route is cochlea implants. These are battery driven implants, that covert sound waves into digital signals that can be sent to the brain via the auditory nerve. I should state this does not restore normal hearing by any means, but does allow victims after training to understand speech.
So the advice is avoid noise abuse. If it starts, then you need to avoid loud sounds like the plague, to avoid speeding up the progression of deafness.