Whether manually or automatically, hyaluronic acid and its corresponding whitening ingredients can be directly injected into the skin through a needle with the help of a water gun. There is a skin barrier on the surface of human skin, which is very dense. Ordinary cosmetics, such as hyaluronic acid, are difficult to penetrate the stratum corneum of the skin and enter the subcutaneous layer, which can not achieve good moisturizing or whitening effect, so that drugs can not enter the skin in large quantities, affecting the role of drugs. Later, doctors and experts invented the water gun, which can beat the effective cosmetic ingredients such as hyaluronic acid under the skin through multiple needles. In particular, the automatic water light can well grasp the depth of needle penetration into the skin, and can also well adjust the amount of water light gun per needle. Hyaluronic acid and cosmetic ingredients are sprayed under the skin of human face by water gun, thus achieving cosmetic effect. The best effect is that hyaluronic acid can have a strong water-locking and water-absorbing effect, and the skin will be moist and tender after completion. It is particularly obvious that it is easier to put on makeup and the skin can also achieve whitening effect. A water gun is much better than a mask alone.