There are several potential causes of dark spots on the lips. Many of them can be reversed with close attention to lifestyle factors that are associated with their development.
For example, dark spots are common in those with chronically chapped lips and those who chew or pick at their lips. In these cases, it is the repetitive minor trauma to the lips that causes the dark spots, and wearing lip balm and refraining from manipulating the lips will usually lead to things clearing up.
Tobacco and coffee are two other factors that are commonly associated with lip discoloration, and discontinuing these may help.
Sun damage is also very common, and it might be important to avoid sunlight and also to use a good sunscreen lip protectant when you go outside.
You should see your primary care doctor
about this issue because there is one potentially serious cause of dark spots on the lips which needs to be ruled out. A new dark spot could indicate a melanoma, which is a very serious form of skin cancer. Your doctor can rule this out with a quick exam in most cases, although a suspicious mole might require a biopsy
just to be on the safe side.
See your doctor at your earliest convenience!