Months ago I performed oral sex on a woman. About 2 weeks later bumps appeared on my upper lip. The bumps weren't painful and some would form in clusters while others were stand alone. The bumps look like those that would appear on your face but aren't consistent with acne as they never come to a head or hurt. They appear about every two weeks and stay for around a week. I've been tested for every std over the past year and have been negative on everything. Anybody know what this could be?