Oxygen is drying to the mucus membranes of the nasal lining so it responds by increasing moisture production to compensate. Check with your supplier to see if the oxygen can be hydrated before it reaches your mask or change to a nasal canula to administer the oxygen. This should be more comfortable.
Do check that your doctor intends you to be on oxygen 24/7 as some patients can cope with 15 hours a day or even less depending on your state of health.
Does your oxygen supplier provide a humidifier as part of your equipment?
Do you use mask or canula?
Thanks for the extra information. Nasal cannulae have been associated with increased trauma to the nasal passages and there is a suggestion that a water based lubricant should be used for insertion to help with comfort. This may reduce irritation of the underlying mucus membrane.
Other alternative would be to try a face mask although people complained about restricted mobility. In extreme cases, where a person has reduced mobility and existing poor health hen a cannula can be directed into the windpipe through a miniature tracheostomy however this is an extreme option if you are otherwise in good health.
Finally do ask your supplier if a humidifier has been connected up to your equipment. there are different types of humidifiers however the feeling ks that all long term oxygen should be humidified.