Why would there be blood in my mucus when i blow my nose?

Inflamed lining: There are a large amount of superficial blood vessels inside the nose and when the lining gets very irritated often there can be blood. You may have a sore or some other irritation in your nose that can be easily evaluated and treated by an ENT doctor.

Picking nose....: I was taught in medical school the 3 top reasons for bloody noses were "picking your nose", "picking your nose", and "picking your nose". So make sure you are not causing any physical trauma to your nose, avoid dry air environment, and avoid other irritants - especially cigarette smoke. Use saline drops to humidify your nose.