I treat wounds here that includes HBO therapy. We have some people who have had 5 days treatment for weeks. No one reports any increase energy, or skin changes etc.
5 ninety minute sessions per week will cost around $1500-$2000 per session.
I’m told HBO clinics abound in Florida giving sessions for several $100 each
Out of curiosity, you might actively make more inquiries as to any other changes those undergoing treatment may have noticed.
Also, research the improved QOL for those with lower than normal o2 levels who are receiving other kinds of o2 therapy; those using continuous positive airway pressure devices for instance.
I would be interested in hearing more about your observations.