Don't squeeze, pinch or pick a cold sore. These actions can cause bacterial infection. Also, because cold sores are extremely contagious, avoid kissing and sharing cups, towels or other such items. Wash your hands frequently, especially after touching the cold sore. And take care not to touch your eyes or genitals immediately after touching the sore. It's a good idea to have hand sanitizer with you in case you accidentally scratch your cold sore and there's no wash basin handy.