If someone has a cold sore and gives me oral sex when they have one what does that mean? thank you doesnt most of the population have cold sores?

It means you can get HSV-1 and if you get it then you could give HSV-2 to a partner if you have oral sex . All this means is you should practice safe sex or come down with a possible STD.

About half the US population is infected with herpes simplex virus type 1, usually with oral infection, but most of these don't have obvious oral herpes oubreaks (cold sores). If not previously infected with HSV1 and you get oral sex from an infected person, you could get genital herpes due to HSV1. However, the chance of virus transmission from any one exposure is usually less than 1 in 1,000.