It doesn't hurt when you have low levels. It might affect different people different ways. I have interstitial lung disease, and for me, i feel lousy, headachy, kind of like high altitude sickness (without the nausea) and only then do I realize that my o2 has run out (a common happening at the rehab place - their tanks didn't have the alarms they should have had when you ran out of o2!). When my o2 comes off at night (not sure whether I yank it off or what), I sometimes have bad dreams then wake up to find it off. I'm dependent on 4 liters 24/7
the oversensitivity is hard to deal with. But here are some suggestions. Take him off sugar, including canned or bottled fruit drinks. No soda. No candy. Sugar causes inflammation.
Something else you might consider is that he may have thrush, with is common for asthmatics and those with other respiratory diseases. Thrush does not always present with white spots, but the mouth may be red and sore. The inhalers he uses encourage the development of thrush. The most common culprit is Candida albicans. This infestation can mimic allergies. The fungus feeds on sugars.
I have emphysema and am currently being treated for candida. My coughing has stopped and there is much less phlegm. Ask your doctor if a fungus is implicated in your son's condition.
I'm not sure why they are low except that he has asthma. He coughs alot and is allergic to smoke, alot of his family members smoke, but not around him. I think the smell of it still trigers it, could that be true?
There is no pain. I have been there. You don't say why his levels are low.
I had low oxygen levels as I came out of anesthesia. I could only tell because the nurse told me to breathe to get them up.
Why does he have this problem? Does he have a lung problem?