STDs are not spread by contact hand to genitals. If they were, we would see them more frequently. Skin in the genital area is so sensitive, so is normal to have small lesions and scratches because of our normal activities or when masturbating or getting masturbated by other people, specially if it's done vigorously.
Typical STD symptoms are smelly white secretions, and circular lesions / blisters. But there has to be oral/anal/vaginal sex in order to get a transmission. Some of them can also be transmitted by sharing needles or other sharp objects, as well as sexual toys.
I would not worry to much in your case. But if you are really concerned about a particular lesion you have in your genitals, you can always visit your doctor.
Al the best.
You say "The only thing that worries me is she soap cleaned my genitals, nothing more." I'm not sure what else you'd expect her to use, but soap is the only cleaner you need to use on your genitals. Anything else is too irritating to delicate and sensitive skin.
You aren't at risk for anything here - as DragonPulse said, hands don't transmit STDs.
Sometimes, a pimple really is just a pimple, or maybe you're having a reaction to the soap that was used. Don't pop it if it reappears, and let it heal naturally. (Never pop pimples - you have bacteria on your hands that can cause infections, push the bacteria deeper into the skin, and leave scars. - https://www.verywellhealth.com/is-popping-pimples-bad-for-my-skin-15523 If you use any products to help it heal, make sure it's safe for genital use.)