First, read the English article below.

The lactic acid in milk not only combats pigmentation problems, but stimulates collagen to improve your skin’s firmness and refines the appearance of wrinkles and lines. You can receive its benefits by dipping your hands directly into milk or milk mixtures, or by buying skincare products containing lactic acid.  Full-fat Greek yogurt is another popular choice. Massage it into the tanned skin, let it sit for twenty minutes, and then wash it off with warm water. Repeat daily. Its fat content also moisturizes!   Lactic acid peels are also available for more extreme, ongoing treatment (in case of irregular, unwanted pigmentation spots in skin), but skin generally takes time to adapt to and fully tolerate the process. Therefore, it's not best for our purposes here. 

Now, please write a short abstract for it in Vietnamese. Abstract:
Sử dụng sữa.