Cold sores (also knows as fever blisters) are a sore caused by herpes viruses (HSV 1 and HSV 2). They are tiny, fluid filled blisters that occur on your lips and corners of your mouth.  For those who suffer with them they are very painful and healing is uncomfortable.  They are very contagious and can be spread by close contact with a person having an active sore.  In the early stages a cold store starts as an itchy and tingly area, then fluid filled blisters form.  These then pop,and ultimately scab over.  Thankfully, we have a medication that can be used when the first symptoms of a cold core appear.  Taking the medication as soon as symptoms start can reduce the severity of the cold sore and sometimes prevent it from coming.