To dream of pimples represents issues with low self-esteem and self-image. You may be self-conscious about something or hoping that a problem you have isn't noticed. You may feel awkward or out of place in a situation or relationship. Insecurity that something is wrong with you. Feeling stupid that your appearances are not as perfect as you'd like them to be. Insecurity about appearances in public or to people close to you.
Example: A woman dreamed of having pimples that needed to be popped. In waking life she had issues with her finances that requiring being dealt with and were embarrassing to talk about. The pimples may have reflected her low self-esteem about being someone with financial difficulties.
Example 2: A young man dreamed of having a pimple on his chin. In waking life he was very insecure about living at home with parents and having to discuss it with friends.
Example 3: A woman dreamed of seeing her ex-boyfriend's face with a lot of pimples. In waking life she was very insecure about her appearances to friends and family with her ex-boyfriend never returning to her as he had found another woman.
Example 4: A woman dreamed of having a pimple on her knee. In waking life she had low self-esteem about her weight and her inability to control over-eating.