I saw a small hair salon and said, what does it mean to punch a hole and knock on the back?

Traditional craft. Traditional barber shop services, such as ear plucking, shaving and drilling, are one of them. There is a hole in the inner side of the lower eyelid, which is called "tear spot" in medicine, but it is actually the opening of the lacrimal passage at the eye. Tears flow into the "lacrimal sac" through this hole, and then enter the nostrils through the internal lacrimal passage, which is also one of the reasons why people cry with runny nose. Punching is to explore the lacrimal passage with hair or other soft and elastic things, which is comfortable and smooth. Some elderly people with a lot of "eye droppings" will "cry" because of obstruction of nasolacrimal duct if they don't "punch eyes".