The reasons why melasma on the face suddenly becomes less include sun protection, repairing the skin barrier, curing related diseases, and healthy lifestyle. 1. Sun protection: If the patient usually pays attention to preventing ultraviolet radiation, melasma may gradually decrease. 2. Repairing skin barrier: When patients use repairing and moisturizing medical skin care products, the barrier function of the skin will be repaired, and then the discoloration may gradually subside. 3. Cure related diseases: If chloasma is caused by the imbalance of estrogen and progesterone levels, chloasma may disappear after the hormone levels are normalized. 4. Healthy lifestyle: when the patient corrects the bad living habits, the endocrine disorder will return to normal, and the melasma may become less. Finally, please go to the hospital for examination if the melasma on your face suddenly becomes less.