Welcome! My name isXXXXX am a UC Davis graduate, and currently, a Medical Director of a veterinary hospital.
I am sorry to hear about this concern for Louie.
It sounds like he has a "bleeder" from the surgery that has caused a hematoma
(blood clot) to form in his scrotum. It is that bleeding
which is causing him to bruise. If the scrotum continues to swell or you observe any oozing from the incision, I would get into an emergency vet for some assistance. Rimadyl
is a good non-steroidal anti-inflammatory that may help some.
If he will tolerate it, you can apply some direct cold compress to his scrotum/incision for a few minutes. Avoid direct ice. Separate by some paper towels so not to uncomfortable.
Sorry to hear about the complication. It does happen from time to time, so make sure to prevent any running or jumping.
Please let me know if there is anything I did not cover for you. I hope that information has been helpful.
Please remember to select Reply to Expert, if for any reason you need further clarification, have more questions, or were expecting a different type of answer. DO NOT rate yet if have any other questions. My goal is to try and provide you the best answer possible.