So basically, an acne cyst is just a bigger, badder, uglier version of a pimple. There's a few different cysts. While a pimple will take place around this level of the skin, an acne cyst is taking place way down here. And the reason it hurts is that the inflammation is in contact with this little thing, which is a nerve that transmits pain to your brain. So usually an acne cyst hurts, while a pimple doesn't. In addition, a pimple you can usually get to go away in a few days, either by itself or using a spot treatment. Whereas an acne cyst, you really need an injection from a dermatologist of cortisone to get rid of that inflammation. Lastly, while a pimple won't usually cause a scar, an acne cyst can. And the reason is, that inflammation from an acne cyst can destroy collagen and elastin, thus leaving a depression in your skin.