Acne vulgaris (or common acne) manifests as comedones (blackheads, whiteheads) and pimples (the more inflammatory stages of papules, pustules, nodules, cysts).
Contrary to popular belief, all acne is hormonal. There are many hormones that affect acne including androgens (testosterones), oestrogens, cortisol, insulin, IGF-1, growth hormones, among others. We can get acne during puberty when the sex hormones are 'raging'. We can also get acne after giving birth and around menopause. We can also get acne during the monthly menstrual cycles or after a stretch of poor diet. Although a minority, adult men can also get acne.
The blackheads are comedones and the mildest form of acne that look like tiny black spots on the skin, usually around the nose. The black spots are a mix of sebum, bacteria and dead skin cells that have been exposed to air.
The whiteheads are also considered comedones like blackheads but are closed within the pore, thus they also block toxins from evacuating. They look like white raised bumps on the skin anc can sometimes be mistaken as milia.
The pimples are red lesions that can be sensitive and painful to the touch. There are different names attributed depending on the size, the depth and severity of the pimple: papules, pustules, nodules and cysts. Pimples usually are filled with pus and popping them or squeezing them can lead to scarring.
However, non-popped pimples can also form scarring (new skin created that is different to the original skin). Scientists are still trying to understand the healing process of the skin, in particular, why the new skin is created different to old skin. But it is understood that a healing process that takes place too fast or too slow risk forming scars. Therefore, it is important to carefully choose acne treatments and avoid harsh products that can derail the skin's healing process.
But if you suspect something more than just acne vulgaris, such as possibly PCOS (polycystic ovary syndrome), itchy fungal acne, rosacea, etc, please consult a medical practitioner.