My wife performed oral sex on me briefly for about a minute or so when we realized she had a cold sore on the corner of her mouth that she has been treating with Abreva for about a week or so. The cold sore appears to be in is in the final stages of healing and looks like it is just about healed up. For background, I myself have tested positive for HSV-1 since childhood (orally) and my wife has also has HSV-1 for as long as I've known her (over a decade, also orally). Should I be overly concerned with potentially transmission to the genitals?  Thanks!

No!  Since you both have HSV 1 already, it is extremely unlikely that either of you would get HSV 1 in a new location.  If I were in your situation, I would not give this a second thought, even for a moment.---