Hello, Reoccurring episodes are common for viruses. Stress can activate a dormant virus. All you can do is treat the symptoms and wait for the lesion to heal. There are medications that can lessen the effect if used at an early onset. Tingling and itching are main early symptoms that are often reported before an episode. Abreva is an over the counter brand available. This is 10% Docosanol. Prescription medication in pill, ointment or lotion form can be considered if you visit your doctor or dentist to have available for these occurrences if you are experiencing this at a high rate. Valacyclovir Hydrochloride is indicated before clinical signs are visible or if you can see a sore. It is a costly medication. This treatment is for Herpes viruses. Viruses do shed and can be contagious. Thank you for your inquiry.