1. Are your periods regular?
2. Have you gained weight?
3. Do you sleep late?
4. Are your eating habits irregular?
5. Do you NOT exercise?
If the answer to any of the above questions is YES, then that is probably why your have is getting 'dull'. That is because an unhealthy lifestyle causes insulin resistance . And that leads to raised androgens thus leading to 'dullness '. Let me clarify here that I'm just speculating. Since I haven't examined your skin it is difficult to prove my diagnosis. So, visit a dermatologist near you. There are treatments available only if you are diagnosed first. Till you visit a dermatologist start modifying your lifestyle. By that I mean that the answers to the above questions must be NO.
Hi. Ideally a photograph would help. If the face is getting darker, I suggest you start taking oral antioxidants (cap. Antoxid -HC one capsule daily after lunch for one month), a sunscreen with spf 30 and up. Also have a balanced diet with fruits and green leafy vegetables. These are basic measures. A skin lightening cream is often prescribed - one which doesnt contain steroids after due consultation with a dermatologist. Many times chemical peels can also help in giving an even skin tone and help in lightening the skin a bit after proper exfoliation (shedding) of the superficial layers. Again all is subjected to individual variations in skin type. Consult a nearby dermatologist to be sure it's not any other Pigmentary condition.
Dr. Zubin Mandlewala