its either an allergic reaction, or cystic acne. last time I had little bumps, it was the first, thanks to baby oil gel [don't ask why it was on my face]. in my case, my foundation got rid of it - the [good] oil in it helped moisturize my face.
not sure which is the case for you, but I'm pretty sure some makeup products or maybe even the products in your skin care regimen could be the cause of it. it could be birth control, if you've just recently started taking it. check all of the products you use to make sure they haven't expired.