Venous lakes are small, raised papules that commonly appear on sun-exposed areas such as the lips.  They are typically benign and asymptomatic, causing no pain or symptoms.  They are sometimes confused with melanoma and should therefore be evaluated by a Doctor.  The cause of venous lakes is not well understood.  The most likely cause is chronic sun damage to the walls of the superficial veins, which leads to the dilation and subsequent papules.