@JurgenG
Many people in this forum regret using headphones after they have habituated because they noticed their tinnitus becoming louder and stayed permanent. When the inner ear (cochlea) has been affected by noise trauma, it is more sensitive to sound even after habituation. Playing music through headphones even at low volume at such close proximity to the ear, risks irritating the cochlea, which can result in making tinnitus louder and more intrusive.
Michael
Are also OVER ear headphone with low level music dangerous? Since you properly referring to in-ear headsets which are not the same as over-ear headsets.