Scar from Compression Garment?

Compression garments don't leave scars unless they cut or damage your skin. What may have more likely happened is that it has left an indentation, and this will go away. What makes you believe that you have fluid buildup? If you don't trust your surgeon, I recommend you see another for a second opinion.

The compression garment should not cause a scar, per se, but would leave marks along the seams the same way that your pantyhose could do, only deeper. That is not a scar, only induration. A tummy tuck, however, would produce a scar and I don't know why you would be surprised by that. All incisional surgery produces scarring which should go on to fade over the course of a year. As for fluid build up, I think you need to discuss this with your plastic surgeon or to explain why you disagree with his judgment. Photos would help.

If the garment was on for one day, and you have a scar, it must have rubbed a blister and killed the skin. It should have been blistered, and red. If it looked like your incision, then it must have been something your surgeon excised. Either way I would ask him about it.