What COULD be wrong? Well, lots of things, I suppose.
What is MOST LIKELY wrong? Probably some inflamed/irritated nasal lining as a result of the cold and the nose blowing. When the cold resolves, this problem should to. If not, you might want to get it checked out. In the meantime, try some nasal ointment (Ayr Gel, Ocean Gel, etc.), nasal saline sprays and keep well-hydrated.