Go to a DR. Infections are never a good sign, especially those that last more than 7 days.
My wife was advised by her DR to clean the posts on her earrings with rubbing alcohol every 4-6 weeks, since you never know what has built up there over time. Are you always sure to touch your ear lobes with clean hands, even if you are wearing “real” jewelry? It was also suggested that every so often she dip the posts into bacitracin or neosporin before putting her earring back on since it could never hurt and you never know what might just be inside that opening.