Oh dear, your vet isn't a good communicator or reassurer is he? A seroma is very comon after surgery. It is an absolutely harmless build up of fluid close to sutures after surgery so long as it is not inflamed and sore looking or weeping fluid. It may well change in shape while it is there for either a long or short time. It frequently happens in humans too. If you really think there is cause for alarm you should make an emergency appointment with your vet. If not, try not to worry please and tell your husband the same My daughters tell me that I worry about my dogs much more than I ever did about them when they were children, so you are not alone. Let us know what the vet says when you go back to get the stitches out please