4 months ago, I noticed a few itchy bumps along the panty line. There were only like 3 or 4 of them total. Two days ago, however, I started my period and noticed MULTIPLE itchy red bumps near the back of the panty line close to my anus . It is only around this area on the left side. None at all on the right. The last time I had any sexual intercourse was 2 weeks ago. What can this be, and how should I treat it?