Pimples, as you know, occur when the pores in the skin get clogged, leading to a buildup of material inside the pore. Usually they are uncomfortable, red, and they end up coming to a head with some whitish material inside of them. Pimples can occur anywhere on the skin, including the skin of the genitals.
Sometimes, pimples are confused with ingrown hairs, which occur when a hair curls on itself and grows back down into the hair follicle. They also cause a reddened bump, but you can usually see the stuck hair, if you look closely.
Finally, it is always important to make sure that skin findings around the genitals are not from a sexually transmitted infection. The most common sexually transmitted infections that can cause sores around the genitals are herpes (which tends to cause blisters, not pimples) and genital warts
(which causes fleshy growths which are not reddened or inflamed).
I suggest that you go see your primary care doctor
or your OB GYN doctor about this issue. They will be able to examine the area and help you determine what might be going on. If there is a need to rule out a sexually transmitted infection, they will be able to perform those tests for you.