Significant swelling causing waterbed effect from hip to hip is that bad?

As all the other doctors have indicated, what you are describing is a classic seroma. Would definitely visit your plastic surgeon for drainage. Best of luck.

You are describing a seroma, which often cause pain disproportionate to its size, and it sounds as if you have a sizable one.  As a fellow healthcare professional, I am surprised you have not gone ahead and contacted your surgeon.  None of us can fix this over the internet, and believe me, your surgeon wants to see you for this!!!!!! A simple in office procedure will leave you feeling dramatically better.  Stop refilling pain pills and call your surgeon so you can be seen and treated.  You are doing the right thing by staying in compression, but it sounds like there is too much fluid for your body to resorb on its own.  And while it doesn't sound necessarily like you are infected, again, none of us can determine that over the internet.  You need to be seen by your surgeon.  You will not believe how much better you will feel.  Good luck!!