Hello,
Flat warts are also called plane juvenile warts,they are benign tumors of the epidermis and usually occur in children. Flat warts are about the size of a pinhead and usually appear on the face, but can also appear on arms, knees, or hands.
Tazorac is a prescription topical retinoid and is basically used for acne. It is true that it can cause itching, erythema, photodermatitis, even dry skin and bleeding. I suggest you to take a second opinion and get an evaluation done from a dermatologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Thank you very much for your suggestion. I will definitely get a second opinion!