👉 Arrived pimples, also known as post-acne cysts or nodules, form when pores become blocked with dead skin cells, sebum (oil), and bacteria, leading to inflammation and the formation of painful, often inflamed lumps under the skin. These cysts develop when the blockage is deep within the follicle, trapping debris and causing the skin to swell and become infected. The result is a hard, painful lump that may not be painful initially but can lead to scarring if left untreated. Factors like genetics, hormonal changes, and improper skincare can contribute to the formation of these pimples.