D.M.
Not to scare you, but in my personal experience, cysts do have a tendency to come back. Over the years I've had several removed, surface, not internal, but they just like cropping up somewhere else. If you're prone to cysts, and have had them before, they can, and sometimes do, come back. If things feel the same as they did the first time, then very definitely go get checked out.
Make an appointment with your GP before hitting up the ER though, it's cheaper at the very least. Hopefully your GP is competent and will listen to you, and take your history into account and get things sorted. But yes, definitely go see a doctor.