Not a diagnosis, but "drying out" is a common complaint of Oxygen use. Loss of taste can also be associated with being dehydrated too. SO moisture does (or does not) circulate throughout the body - affecting other things as it will and at random.

You Doc will probably suggest adding a humidifier (water) cup to the oxygen supply to see if things improve. My suggestion would be to increase fluid intake - especially before meals. The bonus here is eating less also tends to improve breathing in the diaphragm area.
be Well