If it's pigmentation, you can try using VE to wipe it. It's sold in pharmacies, and it's five yuan each. You can also try aloe vera gel and essential oil, which can speed up the removal of pigment traces. Some people say that it is enough to stick ginger on the affected area 15 minutes, and it is also possible to crush vitamin C and put it in water, but I have never tried either, and it is ok to take more baths.