Hello. Skin pigmentation on the face can be due to many reasons. external factors like sun exposure leading to tanning , melasma, photopigmentation etc,.. use of some cosmetic creams causing contact dermatitis, riehl s melanosis etc...
internal factors like hormonal changes can lead to melasma, peri oral pigmentation, lichen planus pigmentosus, etc..so there are multiple causes. you need to consult a dermatologist to find the reason and get appropiate solutions.
Next Steps
consult a Dermatologist
Health Tips
wear sunscreen, avoid direct sunexposure, avoid chemicals and hot water on face