Sun spots, also called solar lentigines, are discrete flat patches caused by cumulative UV exposure. They sit in the upper epidermis and respond predictably to laser treatment.
Melasma is a deeper, hormonally influenced hyperpigmentation that involves both epidermal and dermal melanin. Heat and aggressive light energy can trigger rebound darkening, which is why BBL is not recommended for melasma. Melasma is treated with lower-energy Moxi resurfacing, VI Chemical Peels, and topical therapy over a longer course.
Everis Aesthetic Medicine distinguishes between these two conditions during your initial assessment.