This is education, not advice
The information here is written for the general reader and does not replace a personal medical consultation. It cannot tell you which contributor is causing the dullness on your own face, whether treatment is appropriate for your skin, your health or your circumstances, or whether a treatment is suitable during pregnancy or breastfeeding.
Nothing here makes skin permanently luminous
The surface of the skin is renewed continuously and meets ultraviolet light every day. Whatever improvement a routine or a course of sessions produces is held up by maintenance rather than fixed in place, and anyone describing a permanently luminous result, or a promised number of months of it, is describing something that cannot be promised.
Some dullness is not a cosmetic problem
Pallor with fatigue, yellowing of the eyes or skin, sudden or patchy darkening, darkening that followed a medicine, and any mole that is changing in size, shape, colour or border is a medical finding. It is assessed by a doctor before anything cosmetic is considered, and treating it as a surface problem delays a diagnosis that matters.
Individual results differ
Dullness has several contributors and their proportions differ between people, so the same routine or the same course of sessions produces different amounts of change in different faces. No number of sessions and no degree of improvement can be guaranteed, and no plan can be made properly without an examination.