What Causes Spots On The Face While On Microgynon?

I'm 16 years old, and have been using microgynon 30 for 11 months, and have had no problems, apart from I have small tiny bumps (kind of like spots, but theyre not red/white/yellow or black) on my face, the bump-like spots are on both of my cheeks, one side worse than the other.. I was just wondering if anyone has any ideas of what this could be? and how I can help/treat it? Thankyou.