What Causes Greenish Mucus With Black Specks And Pain In The Side Of The Face?

I have had a head cold for a week. For 2 days I have increasing pain in one side of my face, severe pain in my 2 back tooth/jaw on that same side. When I blow my nose, the musts is green and yellow and now has 1small black spot. But the black is there every time (for 2 days!) Im really worried. The pain is terrible as well. What could a recurring small black spot be in mucus?