Shitzu - blackheads on belly?

Question
I have a 12 year shitzu that appears to have blackheads on her stomach.  I took her to the vet a while back and he said it was normal. Now, I notice she's having white and some times green puss filled postuler.  I've also noticed these sores - which seem like it's decubitus - It's all quite gross - I try to make sure I bath her regularly as because she's older and has problems with her hind legs - her urine tends to collect more on her hind end than normal dogs who are able to squat properly.  Have you ever seen anything like this in your many years of grooming?

Thanks in advance.

Answer
Hello Nikki, I might have seen something similar, If you think this skin condition is mostly caused by the urine, then try using what parents use for diaper rash (something like desitin), or Vaseline, this will repel the urine and in doing so keep it away from the skin.  Also you might want to apply some antibacterial creme if you think it looks a little infected.  Good luck and Thanks for asking, Cindy Lou :)