I had a cold sore for three weeks and i don't know if it's healed yet. it's still a bit red but i'm thinking maybe it's just a scar. is it contagious?

Less contagious.: Most of these are HSV1 and most adults already have it without any symptoms. So whoever you kiss either has it or will get it anyway. You shed viruses periodically so you might transmit it between attacks, but you are most contagious at the beginning of a sore.

Not likely: If you had a cold sore and all that remains is some redness, it is probably the result of the inflammation remaining after the cold sore ran its course. If the little white or clear-looking bumps (called vesicles) have dried up and gone, the area is no longer contagious. The virus that causes the cold sore can certainly be spread to others when the vesicles are still present.