It works by stimulating collagen in the skin, because the roller needles make holes in a layerThe dermis with the skin, which stimulates the immune system to build collagen and elastin during the healing of these holes..and thus build a healthy skin layer and get rid of scars and fill deep cracks in the skin..as collagen is responsible for the cohesion, strength, activity, youth and vitality of the skin, in addition to that during the work of holes It allows the skin to absorb the largest amount of therapeutic active substances that can be used to build collagen for the skin.. It may not hurt or it may hurt a little according to the measurement and you will feel a slight tickle and your eyes may tear or sneez when you try it for the first time on the cheek.You will notice a slight redness on the skin, and this is evidence that the needles penetrated your skin and benefited from them. Within two hours, God willing, the redness will go away. Does the derma increase the benefit of the product that is used after it? As for the use of therapeutic cosmetics “alone”: Studies have proven as on an official foreign site what is the textAnd translated in a nutshell: Any cream, gel or solution you put on your skin benefits your skin with a maximum (0.3%) of it only, meaning that (99.7%) of the active and active ingredients (which is the vast majority) is lost without penetrating the skin enough. I would like to add this study also for information: Dr. Philip Simon, a famous Swiss dermatologist, conducted a study on 600 people, some of whom are Africans, who had problems such as wrinkles, scars, cellulite and cracks, and the result was after exposure to only 6 treatment sessions as follows: - 40% improvement in terms of skin aging 60% improvement in scars and acne scars _ and cellulite