If you have a pimple-like lesion, or you have any kind of spot on your skin that seems like it's an acne that's lasted more than a month, or you have an area that's seeping something that might look like plasma or puss or blood, and it persists over a long period of time, like a month or more, absolutely get that checked out by a dermatologist. Okay, don't wait longer than a month. Get it checked out.