Having a common cold does not cause a cold sore; the herpes simplex virus causes it. They are very contagious. Some people call them fever blisters.

Cold sores are very common, though they cannot be prevented, you can reduce the frequency and duration of them.

The first telltale sign of a cold sore is the tingling on the lip and hard spots that you can feel but not see in the mirror. In a day or two red blisters will appear where the hard spot was.

The blister is on a red, and painful area of skin. The tingling is called "prodrome" and often arrives a few days before the blister appears. The cold sore itself can last up to 10 days. Cold sores usually will pop up on your lips. You can occasionally get them on other places as well, such as your nostrils, fingers, roof of your mouth, gum line, and also hard palate, and you may get them on your chin.

Once exposed to the herpes simplex virus it could take as long as 20 days before you will see evidence of a cold sore. Usually there is no scar after the cold sore has healed.

There are different strains of the herpes virus, with the one causing the cold sore being herpes simplex virus type 1. The type 2 viruses are the culprits behind genital herpes. You can get sores on the facial or genital area from either of the two viruses. You can pass along the cold sore by sharing utensils, razors, towels and other personal items where there is a touching of the cold sore with the item and then someone else touches the spot where the item touched the spot.

The virus will remain dormant in your nerve cells and then become active again at some later date. Sometimes stressors can bring on cold sores such as when you are under stress, have a fever, are menstruating, or are exposed to the sun.

It is important to see your doctor if you have a weakened immune system and have a cold sore, the cold sore does not heal within 2 weeks, your symptoms are severe, you have many recurrences of cold sores or if you should experience irritation in the eye area.

The complications of cold sores are that they are contagious so you can be passed onto others in your family. The biggest contagious period is when the blister is visible.