It did not work very well OR for too long with mY cat, but if your cat is more sedate, perhaps it will. Here are some progression photos with her on Clavamox and applying Neosporin to the incision site.
06/22/10 the day I took her in to be seen
06/25/10 - you can see the size of the seroma to the right side of the incision
06/27/10 - seroma seems to be shrinking
06/29/10 - forgot to get a pic on the 28th. Look at her cute face! :) Her incision has a jagged appearance but is pretty much healed by now. The seroma is still in attendance.
It looked like the seroma was coming to a head last night but not so much today.