It sounds like your current Vet is either in a state of denial about doing a poor surgery, or is totally incompetent.

My little Barney had what one would expect - a slight swelling along the incision. If the stitches are not close enough together sometimes there is a little seepage.

What you are describing is a major blood vessel that wasn't tied correctly, resulting in a massive amount of blood filling and distending the empty sac.

A second Vet may choose to reopen the incision take out the now massive blood clot, check the internal ties, and then sew up again. It's possible for the blood to be reabsorbed internally, but that really presents an optimal environment for an infection to occur.