Cysts are large pimples under your skin. As they fill up, they become inflamed. After the inflammation soothes down. the sac still remains which can become inflamed again. These pimples will never come to a head, will take longer than usual to disappear and will even leave a scar behind. These are mostly caused by hormones and as they are so much deeper than a regular pimple, they’re more difficult to treat. Do not pick or squeeze them because they might not be ready to come out and can infect other nearby areas on the skin too.