Flat warts, or Verruca plana, are benign skin growths caused by infection with the human papilloma virus. They are small and flat and tend to occur in large numbers, typically on the face or legs. Tazarac is a retinoid medication similar to vitamin A that can treat flat warts by inhibiting the replication of HPV, thereby regulating keratinization to allow healthy skin to grow in place of the warts. Flat warts sometimes disappear without treatment, according to the American Academy of Dermatology, but they can be treated for cosmetic reasons or to prevent spreading.

Wash your hands and the affected area with warm water and a mild soap. Do not use alcohol-based products or astringents, as these product might be drying and increase skin irritation when combined with Tazarac.

Wait at least 20 minutes after washing before applying the medication. This will ensure your face is fully dry and will help minimize irritation caused by overstimulation of your skin.

Apply a water-based moisturizing lotion to the affected area to hydrate the skin and minimize drying caused by Tazarac use. Allow the lotion to dry thoroughly before using Tazarac.

Cover the warts with a thin layer of Tazarac, then gently massage it into your skin. Use the amount recommended by your doctor for treating your flat warts. Tazarac.com states that using more of the medication will not speed up treatment and might cause increased irritation.

Skip any forgotten doses and return to your regular application schedule. Drugs.com warns against making up missed doses or applying a double dose of the medication.

Use Tazarac once or twice each day, depending on your response to the medication and your doctor's instructions.

Wear sunscreen at all times if sun exposure is a possibility while using Tazarac to treat flat warts.