Signs before the regression of flat warts include slight itching in some people, or a numb sensation in others. During the healing process of flat warts, immune cells repair the local skin lesions and release inflammatory factors, causing mild itching. The rash of the flat warts will also turn red, gradually shrink, and then scab over. If the flat warts have been treated with liquid nitrogen freezing or laser, there might be some pain before they regress. However, before the regression of flat warts, many people do not show any special symptoms and most people's flat warts regress unknowingly. The occurrence of flat warts is due to a viral infection, and they can be removed under the guidance of a doctor using liquid nitrogen freezing treatment or laser methods.