Cold sores are small, painful, fluid-filled blisters or sores that appear on the lips, mouth or nose. They are caused by a virus. The sores can be painful and usually last a few days. Cold sores can often recur.
Mild uncomplicated eruptions of herpes simplex require no treatment. Sun protection (hat and high protection sunscreen) can help protection by reducing exposure to UV which is known to trigger facial outbreaks. More severe outbreaks of infection may require treatment with an antiviral agent.
You can take steps to guard against cold sores, to prevent them from spreading and to avoid passing them to other people.