Is this swelling or fluid post tummy tuck?

Hello, I had a tummy tuck 4 months ago. I swell in the evening but have a flat tummy in the morning. If i tap the area to look for the waterbed effect it doesn't happen when standing but does a little when lying down. There is also a little white bump which may be a stitch? Looking down looks swollen both day and night however a diet in less salt does make it flatter? Please advise thank you