I Have A Hard, Fixed, Sore Pea Sized Knot At

I have a hard, fixed, sore pea sized knot at the very top of my nose on the right side. No injury, no eye irritation or watering, no sinus irritation. If you drew a straight line from my eyebrow to the inside corner of my eye and formed a triangle to the nose from each point you would feel it. It feels as if it is stuck the the bone of my nose. It has been there for about a week. What can cause this and should I see a doctor?