Excess pigmentation can be caused by a number of different factors, such as extensive UV exposure, ongoing trauma from an injury, changes in hormones and hormone imbalances, aging, medical and genetic conditions. Your doctor should be able to refer you to a skin specialist that can help you identify the cause of your skin pigmentation and complexion changes.
It’s important to be open minded, but also to be strong enough to know an expensive bottle of good for nothing when you see it.