The sebaceous glands in your skin produce oil (sebum) every day to help keep skin healthy. During puberty, around the time of your period or when you’re feeling particularly stressed out, hormonal changes in your body can lead to overproduction of oil on your face (particularly your t-zone which is made up of your forehead, nose and chin), scalp, chest & upper back as these are the areas of your body that have the highest concentration of sebaceous (oil producing) glands.
Spots form when the oil (sebum) your skin produces gets stuck in your pores. Pores can easily become blocked with dead skin cells & dirt if they’re not washed away daily.
Oil and spot causing bacteria can build up inside the pore and can cause swelling in the surrounding skin.
This leads to a small, hard bump with a white centre which you can see and feel on your skin. This type of spot is called a whitehead.