The chances of getting herpes from this are very, very low.
You had just a sliver of skin exposed, and it was brief.
Even if you were in a long term, monogamous relationship with someone with herpes type 2, and all you did was avoid sex during outbreaks, you'd have a 4% chance PER YEAR of getting it.
Using condoms drops that to 2%.
The chance that you got herpes from a one time, fully (and then some) protected encounter is very, very low. I wouldn't even worry another second about it.