Was it insertive oral / vaginal / anal exposure? Also, did you use a condom?
Yes, more information would be helpful. If it was unprotected vaginal or anal, that is a slight risk. Very low, actually. The statistic is less than 2 percent for a single exposure with someone who is hiv+ (and zero if they are not hiv+) and yours was so very brief. When did this happen? If it was a month ago, test with a 4th generation. I'm sure it will be negative.