A negative IgG test five weeks out from a sexual encounter is definitely a good sign. But the thing is, the HSV that would result from receiving oral sex is HSV-1 not HSV-2. He mentioned that you had HSV one result and that you may have had a cold sore as a child or young person. This is likely the source of your positive it just be one infection rather than genital infection since you already had it orally.
Once you have a scene of the virus in one location in your body, you are very unlikely to get that same strain in a new location. I don’t think you need to be concerned about HSV-2 with this sexual encounter. While it is possible for someone to acquire HSV-2 orally, it is rare and when it does occur, it is rarely given off from the mouth subsequently
Terri