I don't know where you live but in Philadelphia, the Hospital of the University of Penn. has what they call the Pigmented Skin Lesion Clinic. They see patients who have had melanoma or a strong history of the disease or patients with dysplastic nevis or those possibly like yourself with many freckles and moles. The will have pictures taken of these moles as a reference. Then they can check to see if there are any changes in the moles such as size, color, thickness, borders. You should look at your skin monthly, the best guide is change. It could be an old mole or freckle that suddenly appears different and is continuing to change or it can be a new mole that continues to change. It might be a good idea to try to capture pictures of questionable areas. My derm has taken pictures from time to time to help him in following me.