A sensory neural loss is not reversible.
3) A third major difference between a conductive and a sensory neural hearing loss, is that the latter is not reversible. A doctor may be able to check the advance of the loss but he cannot recover what has been lost.
There are two exceptions to this. One is the Temporary Threshold Shift and the other is the Cochlear Implant.
You may notice when you have been in a very noisy environment such as a rock concert, that when you come out everything is somewhat hushed. The cells of the sensory neural unit are depleted of the materials they need to function. In a matter of hours, they will regenerate and you can hear normally again. You have experienced a Temporary Threshold shift.
You can experience similar phenomenon if you try to hold two books out at arms length for 15 minutes. For most of us our arms will sink despite our best efforts far short of the goal.