You cannot catch any STD by the kind of contact you describe. Your description suggests your scrotum lesions are pimples, sebaceous cysts, prominent hair follicles, or some other normal skin variant. But of course I cannot tell; the only way to know for sure is to visit a health professional in person. It definitely isn't herpes; it probably isn't molluscum; and whatever it is, you did not catch it during the exposure you describe.
Good luck-- HHH, MD