Thanks for the question. This is a common finding after a direct trauma to the middle of the nose.
The internal framework of your nose may have collapsed most likely from collapse of the middle third of your nose.
The speptum holds the cartilage structures well supported. Any displacement or dislocation of the septum makes the lower and middle third of the nose collapse and flatten.
You need to be examined to make sure that is not the case. Another important factor is that your surgeon needs to rule out the presence of septal hematoma. This condition is formed when the blood accumulates between the septum mucosa lining and cartilage.
Most likely, if your septum has been severely traumatized, you need surgical intervention to fix it.