Sir I Saw A Patient In My Op With A

Sir i saw a patient in my op with a history of getting massage by an girl and she masturbated him and he has sucked her nipples and thats all had happend no other intercourse was there. He said that at the end she wiped of with a towel which he says he is not able to remember that it was wet or dry.
Then after 7 months he has done an elisa which came negative. Now he s complaining of mild groin pain. Kindly guide me about the status of hiv is there a chance of becoming a possitive? ?