Explanation: As the parts of the headband and earphone cushion where the hair touches the equipment is affected, I suspect that something you use in your hair has reacted with the materials used on your headphones.
If the surface is broken or pitted, there is little that can be repaired. You can try some pressure sensitive cloth tape to cover the area. If that is not acceptable, replacement is another alternative.
If the surface has some sticky material that can be removed, try a drop of mild detergent (blue Dawn has no additives and rinses cleanly) or your usual shampoo on a damp cloth to remove it. If that doesn't work, contact the manufacturer for their recommendation for the material they used.
Contact the manufacturer customer relations department for their opinion on how to proceed. Their knowledge base might have similar solutions to similar problems. Identify your hair care materials in the chance they have already had some experience with exactly the problem you identify.
It seems unlikely but possible that you can get a refund or replacement if there is something wrong with your equipment since it is relatively new and you have evidently taken excellent care of it.
Lastly, is there a chance that someone had a problem when they borrowed your headphones without your knowledge or permission.
Good Luck !