Hi, MaxnJens mum. So sorry you and Max are going through this!
If it's a deep-rooted infection it may take a while longer for the antibiotic to work--perhaps it just needs a little more time?
Did they run blood work to make sure he wasn't reacting to the Rimadyl and the Previcox? Both these drugs can be hard on the body.
My heart goes out to you--I know how difficult it is to see Max suffer without knowing what's wrong or how to fix it!
I hope you find some answers soon!
