Lip freckles are mostly harmless and are a natural result of sun exposure. If you are genetically predisposed to freckles, exposure to the sun will make them more likely to appear. Freckles can develop on sun-exposed skin areas, including your lips, because they are still part of your epidermis. The epidermis is the outer layer of the skin all over your body. Although they aren’t usually dangerous, watching your spots is best. Tell your dermatologist as well if you observe any changes.