How can uneven tone of skin be changed?

Dyspigmentation. The first step is adequate sun protection. Darker skin tends to darken quicker with ultraviolet light exposure. Sunscreen minimizes the sun's effects. Topical lighteners (retinol, tretinoin, hydroquinone) must be used cautiously, as they may *cause* irregular pigmentation. Also, control of eczema or other dermatitis must occur, or pigmentation will not normalize.