herpes is the worse because it doesn't go away every time your immune system goes down under it appears even when you have a simple cold it will appear
you can also get mononucleosis, which can put you out for months and cause organ failure in some cases - especially spleen ailments later in life
Mano and Herpes (In other words a cold sore...) Mano is spread thru saliva and is treatable it just makes you very Tired moody and you get a sour throat...