Hi John - welcome to Apnea Board.
Lack of proper sleep can have all sorts of negative effects upon the body. And of course, these issues can affect the way we "look".... tired eyes, puffy face, etc. If your machine is from 2006, it's possible that the machine isn't functioning the way it used to, or it's possible that your pressure needs have changed, and the machine is not now set on the most effective pressure. You may need to adjust your pressures slightly.
To do that, see this page:
If you need the Clinician Setup Manual for your machine, you can get that free, here:
What version of 2006 REMstar do you have? The Plus, Pro or Auto? The Autos are generally better, because they will adjust to your needs on an ongoing basis, rather than delivering a single, non-changing pressure all the time. A data-capable machine is even better, because you can monitor your progress using some free software like SleepyHead
The average useful lifespan for most CPAP machines is about 5 years. Your 7 year old machine may need to be replaced with a newer machine with better internal firmware which will be more effective to control your apnea events.
For advice on machine choices, see this article by Archangle: