I'm inbetween doctors and will be running out of metformin 500mg for my pcos. are there any concerns about not taking it?

No: Hi. No, you can be off for a period of time and start back on it with no harm done. You may need to titrate the dose back up if starting back at full strength causes GI problems; that may depend on how long you're off it. Most new doctors you're going to see will give you enough to cover your needs until your scheduled appointment. Good luck!