Flat warts are a skin condition caused by human papillomavirus infection, and treatment can involve cryotherapy. There are some precautions to take after cryotherapy for flat warts. First, you should avoid getting the area wet for a week after the treatment. Second, it's important to prevent bacterial infections. If redness or pain occurs, apply some anti-inflammatory medication. Lastly, it is advised to follow a light diet, avoid smoking and drinking alcohol, and refrain from consuming spicy and irritating foods.