well, probably, you had a negative IgG test shortly before giving oral sex to them, yes?
I’ve not see HSV 2 orally present only as bumps on the tongue, but clearly it can happen.
The good news is that oral HSV 2 rarely recurs and essentially protects you against genital infection.
If it were me, given how rare HSV 2 oral infection is, I would be tempted, down the road a ways, to do another IgG test and just see what you get. Not absolutely necessary but I would, just as a matter of curiosity.