I doubt the O2 helped you heal from a physiological point. But it may have helped you improve your blood chemistry, especially to your brain so that your brain has more energy. It would be interesting to ask the doctor if there was anything in your blood chemistry besides your O2 levels that improved with the oxygen therapy.

A simple way to self test for this would be to get a pulse oximeter. They can be purchased online or at local drugs stores or medical supply companies. They can cost as little as US $15.00.

Having one in the house would help you rule out O2 issues when you are experiencing brain fog.