Absolute zero risk for HIV, both because it can't be transmitted that way and because the girl probably didn't have it. The risk for any other STD's is slim to none.
if i were a male AND had to resort to a lapdance to get my cookies...i'd probably have a "itchy scrotum" after all that grinding, as you say.
There are tons of questions like yours to doctor H that you could have checked out in the forums. Zero risk at all.