Found this at
http://www.justanswer.com/JA/ASP_ASK...breed-dogs.htm
Q:The color of my dog's penis has turned a white color
A:This could be a circulation issue in that area or over the whole body. Check the mucus membranes in his mouth and under his eyelids to see if they too look pale where they are usually pink.
If its just the penis it may be a problem with the prostate or another issue cutting off a blood supply to the area.
You should see your vet about this
Maybe a complication from the surgery?