you said the person has genital herpes so the answer would be most certainly not unless he/she dipped his/her genitals into the sauce. even then it probably wouldn't be a problem. it takes intimate contact to contract herpes.
can you contract herpes from some one if they double dip in a communal dish? . i shared a dipping sauce with someone that has genital herpes. they double dipped their food into the sauce and i continued to share the sauce. should i be worried about contracting the virus?