Saturday night, I preformed oral sex on my girlfriend with no sign or symptoms of a cold sore. I don't mean to go to into detail but I am sure that my lips did not touch her vagina. In other words; I just used my tongue. Sorry about that detail,it was just to give more info. Monday afternoon I felt with my tongue, and saw a forming cold sore on the top left corner of my mouth. Now I have had cold sores since I was a young child and get them at least 1-2, and I usually know, if not all the time whether I'm getting one or not. I'm on suppressants (Valtrex), but I only take it when I have an outbreak or think I'm getting one. What I'm asking is that even with getting a cold sore basically 2 days after the oral sex was preformed, could I have possibly given my girlfriend HSV-1 genital and if so what are the chances or probability. Please help, I'm really worried. Also I asked her if she has ever had a cold sore in her life and she believes she may have had one when she was younger.