Flat warts are caused by human papilloma virus infection. Before improvement, there may be redness at the base of the lesions, itching and discomfort or a sudden appearance of a large number of small lesions, which are signs of improvement. If warts appear, it is advisable to treat them promptly, because scratching warts can easily lead to an isomorphic reaction and inoculation on normal skin. The actual fact is that you can find a lot of people who are not able to get a good deal on a lot of things. Those with less lesions can be treated with liquid nitrogen cryotherapy, carbon dioxide laser therapy, trichloroacetic acid etching therapy or electro-ion cautery therapy in a regular hospital. Pay attention to not scratching and stimulation, and pay attention to sun protection after treatment to avoid pigmentation.