Injection of whitening needle can improve the dark yellow skin of the whole body, which generally takes 1-2 courses of treatment. I suggest you inject it in a regular medical institution, and the dark yellow face can be improved synchronously with laser. The main component of whitening needle is antioxidant, which helps the body to detoxify, resist cell oxidation and reduce the formation of melanin. It is harmless to human body, and the general effect can last for about 1-2 years. If you stop, you can take vitamin C, whitening skin care products and other methods to maintain. You should do daily basic maintenance and regular medical beauty care.