Never had a cold sore. just developed one directly under my nose. what does this mean?

Exposure to HSV: This means that at some point, you have been exposed to someone who has had a cold sore, or carries the hsv (herpes) virus and was 'shedding' virus. Transmission can occur even if a cold sore is not present, fyi.

Either...: It either means you have been exposed to the virus that causes cold sores and will continue to get them at an unspecified interval or that this isn't a cold sore. Surface bacterial infections at the opening of the nostrils are common as well. Consider using a topical antibiotic ointment to soothe the sore and perhaps make it go away more quickly, then cross your fingers and wait.