Didn't you used to post tons of these massage therapist STD questions under another ID
I don't think any STD would have made it through a towel. As gymdandee says, unless you had broken skin on your hand, you are not at risk from brushing her vagina. I assume you washed your hands after the encounter.
I don't know what forum you want but as long as you don't have any open cuts or wound I wouldn't worry