I think I've tried EVERY concealer and treatment for my hereditary dark circles. I'm finally getting good results from Olay's Regenerist ProX Eye Recovery complex. It's not cheap, but cosidering thow much money I've wasted on other products, I'm happy to pay it if it works. If the dark circles persist after two years, it's not the pneumonia...could be allergies which are often triggered or exacerbated by something like pneumonia, or it could be the weight loss (and resultant collagen loss) that's the culprit. In which case, dermal fillers will help a lot.