Oh, and I had a hematoma on mine and it took it about 3 weeks to re-absorb. The fluid seemed to go pretty quickly :)
Did they take the drains out too early? japdip is correct, needle aspiration will help this situation and oddly enough you won't even feel it as it happens, just the relief that the swelling is down.
The more exercise and walking you do the more fluid your body creates so you may want to consider taking it very easy for a while.
Best wishes.
If you are talking about a seroma at the surgical site, it takes a considerable length of time. If this is the problem the Surgeon will often drain the area with a needle OR even replace a drain until the amount of drainage has lessened to nearly none. Regards ....