Do hairs in the ear respond to things like shampoo?
You are mixing up hair cells and hair. Hair cells in the cochlea (wiki) have tiny stereocilia (subcellular organelles) that sense vibrations approaching the atomic scale. These are then translated in hyperpolarizing or depolarizing currents that drive the spiral ganglion cells of the auditory nerve. The 'hairs' on the hair cells will not readily benefit from shampoo I'm afraid. If you should want to test it, the shampoo should be intracochlearly administered in the scala media of the cochlea - so even if shampoo is beneficial it would be hard to utilize it without surgical intervention.