👉 Assembly pimples, also known as comedones, form when hair follicles become clogged with dead skin cells and sebum (oil) from the skin's surface. This blockage occurs when pores become enlarged, trapping these substances and creating a small, round bump on the skin's surface. There are two types: open comedones, where the pore is visible and filled with debris, and closed or follicular comedones, which are plugged but not open. Over time, if the clogged pore becomes infected, it can develop into a pimple, which may appear red, swollen, and painful.