I'm sure you're used to your doctor saying: 'It's just a virus!' Viruses are tiny germs. You can't see them with the naked eye. They are all around us and are usually harmless (the common cold is caused by viruses, for example). On the other hand, some can be really bad for you if untreated (like HIV).
This is a companion discussion topic for the original article at https://patient.info/childrens-health/viral-skin-infections-leaflet