It will only make things worse. Toss your toothbrush, which can carry the virus. Always apply sunblock to eliminate the risk for sun-induced cold sores. Use one that has an SPF of 15 or higher. Lipsticks with sunscreen will also do the job. Wash your hands immediately after you touch the sore and never touch your eyes. Because cold sores can spread the virus easily, also avoid kissing or sharing cups with others. Among the triggers of a cold sore are dental work, fatigue, stress, sunburn and infections. To avoid coming down with a cold sore, eat healthy, exercise and get plenty of sleep. Also avoid acidic and salty foods, which can make matters worse. Another at-home remedy that most people aren't aware of is the power of glycrrhizic acid, which is found in licorice. Some people swear by it - so invest in a bag of licorice made with licorice mass. You might also purchase some licorice powder and sprinkle it on the sore.