If you have a lot of big blisters in the late stage of flat warts treatment, you can go to the hospital for blister extraction and local topical medication. Flat warts are a viral skin disease caused by human papillomavirus infection. The lesions are flat papules above the normal skin, round or oval, and there are usually no conscious symptoms, and some patients may have a mild itching sensation. After cryotherapy, blisters may appear on the treated area. If the blisters are large, you can go to the hospital, the doctor will use a sterile syringe to draw out the blisters, local povidone iodine to disinfect, and follow the doctor’s instructions to use mupirocin ointment and other drugs, to avoid trauma infection. The flat warts are contagious, the patient should pay attention to personal hygiene, avoid scratching the affected area, to prevent contagion, during the treatment period to follow the doctor’s instructions, cooperate with the doctor for treatment, and monitor the development of the disease, once the discomfort, timely inform the doctor.