infographic of normal and melasma skin on woman face .

melasma skin melanin pigment hyperpigmentation layer spot melanocyte melanogenesis blemish cell dark spots face damage epidermis dermis photoaging woman freckles pigmentation inflammation uva uvb rays premature cartoon aesthetic ultraviolet structure anatomy mechanism prematurely ages dullness vector flat design diagram infographic healthy unhealthy dermatology cosmetology aging beauty comparison care facial tissue discoloration