Spontaneous swelling on my left cheek.

I have been experiencing spontaneous swelling on different areas of my left cheek, sometimes near the mouth, sometimes on the cheek bone, sometimes on the jawline. There is no pain, no itching, no tenderness and no problem to chew nothing at all. The swelling is subsiding in 3-4 days on its own. I have no current dental issues. But I have had an Aortic Valve Replacement surgery in 2012 and have been on anti coagulants ever since (Acetrom and Asprin). I have seen the cardiologist, A General Surgeon and General Medicine as well, my PT INR results are consistent. The General Surgeon found no specific cause, however the General Medicine doctor found I have B12 and Ferritin deficiency and corrected them. But the spontaneous swellings are still occuring. Nobody seems to have a clue about why it is happening. Someone please help me out with this. Thanks