Consult a hematologist on nasal surgery
As stated previously, the nose is quite vascular. During nasal surgery we take extra measures to reduce the bleeding from the nose.
Lovenox is designed to thin the blood, and generally increases the bleeding tendency.
The best approach for you would be to consult with your hematologist to determine what actions, if any, can be taken to allow you to undergo nasal surgery.
Your plastic surgeon in conjunction with your hematologist would determine the best course of action.