Acne results from a build-up of sebum and dead skin cells in the entrance to the skin pore which then becomes inflamed can result in whiteheads and blackheads which can also become tender and sore. There are various reasons you can develop acne including hormones, medication, pregnancy and it can even be hereditary. It's important to develop a good cleansing routine without drying out the skin. Opt for a cleanser designed to gently cleanse and exfoliate without damaging the skin barrier. Follow with a lightweight serum or gel to target your problem areas, moisturise and finish with an SPF before applying any makeup.