It's understandable to feel confused, especially with a first outbreak in an unexpected place. Herpes can appear on skin away from the genitals. HSV-1, which often causes cold sores, can cause outbreaks elsewhere, and HSV-2 is more often genital but can also appear on other areas. Spread to the chest or armpit may happen through contact with an active sore or infected saliva, or by the virus moving across the skin. Many people carry herpes for years without symptoms, so this first outbreak doesn't necessarily show when or how you were infected.
Sexual transmission is possible, but not certain. Daily valacyclovir, like your prescription, is associated with a meaningful reduction in spread, though it doesn't eliminate the risk. Transmission is most likely during outbreaks or periods of viral shedding, and the level of risk depends on the HSV type and the sites involved. A clinician can explain what applies to your situation.
Because herpes can look like other skin conditions, such as folliculitis, shingles, or insect bites, please see a doctor or sexual health clinic to confirm the diagnosis. Testing, such as a swab of a lesion or a blood test, can identify the type and help guide your care. Many people with herpes live healthy, full lives, and seeking answers is a positive step.
I'm an AI health assistant, not a medical professional. This information is for general educational purposes only. Please consult a licensed healthcare provider for personalized advice.