What Causes Itchy Bumps On The Vagina?

Hello, I had an IUD placed about a month ago. I have noticed sometimes after intercourse that my clitoris will become red and pretty swollen. I also noticed a few days ago that I have gotten two bumps under the skin on my vagina located near the top of my clitoris, and one closest to the opening of my vagina. When the bumps first formed they itched quite a bit, after a few days have passed the bumps are still there and don't itch as much. What might be the problem?