Itching and redness in groin, that may spread to the genitals, inner thighs, buttocks and anal area, could be a fungal infection of your skin known as jock itch.
This infection usually appears in warm, moist areas like skin creases.
Scratching the red patches that are itchy, may spread the fungus and also, may lead to bacterial super-infection (the pimple like growths you had in your pubic area)
Usually, this condition is easily treated with over the counter antifungal ointment, lotion, powder or spray.
Keeping the area clean and dry, avoiding tight clothes can be beneficial in therapy of jock itch.
Best wishes!
Marija