I have a mole that hasn't ever changed except 2day it developed a red ring around it. not tender.what r possible causes of this?? could it b bad sign?

Ask your dermatologi: st for sure. If your dermatologist has been keeping a mole map on you, then if something is irregular about it, they are the first and best one's to definitely discuss it with. Need to see why you see a red ring? Is there any pimple, folliculitis around it? Is it blood vessels, or just a reddish color? The physical exam/inspection is key to determining if it's normal changes, or not. Call your Dr.