Hi Braddy,
I’m also 4 weeks post op. I have had fluid which has come and gone all by itself (I could actually feel it sloshing about when I got up or walked down stairs). The longest it has been there has been about 4 days and then it just seems to go by itself. Other times it has only hung around for a day or so. I haven’t been unduly worried by it.
If you are concerned why not talk to your PS?