It is normal for warts to become black and hard after freezing, and there is no need for special treatment. The warts can fall off by themselves in about 2 weeks, and if they do not fall off, they can be frozen again. The actual freezing of the warts is a common treatment for plantar warts. During the freezing process, the warts may bleed at the root of the warts and the tissue will be necrotic, and the warts will be in a blackened and hardened state, which is a normal phenomenon. It is normal for the warts to appear black and hard. The warts will usually fall off in about 2 weeks after the freezing process, but there may be cases where the freezing process does not work, so it is necessary to freeze the warts again after 2 weeks until the warts fall off. During the course of the disease, we should pay attention to keep the local skin clean, avoid scratching and stimulation of the warts, so as to avoid spreading warts, resulting in the aggravation of the lesions.