Campho-Phenique Cold Sore Treatment with Drying Action dries the cold sore and stops pain on contact. Campho-Phenique Cold Sore Treatment with Drying Action dries the cold sore and stops pain on contact Use in the early stage of a cold sore before the scab forms Dry the cold sore without causing cracking, helping to prevent infections to promote healing Relieve the cold sore pain with a maximum strength pain reliever