A pimple in your ear can seem strange. But just like skin elsewhere on your body, the skin in your ears has pores that can get blocked due to the build-up of body oils, sweat, and dead skin cells.
This is what gives rise to a pimple. The formation of a pustule (pus-filled pocket) can cause swelling and redness.
When a pimple occurs in the ear, however, it can cause outright pain due to the inflexibility and lack of fat within the ear and ear canal. Check the video below