What Causes Red Bumps Around The Vagina?

I have recently noticed about a couple days ago that I have red bumps around my vagina that consists of pus in them, just little itty bitty things, which are itchy. The other day was worse after sexual activity, it was burning, swollen, tender, with light discharge. As if today little bumps remain with itchy sensation. What could it be? I m 19, no children with the paraguard iud. Please email me at YYYY@YYYY