Well it's not been the best of days. I feel like I've cried for most of it. Mikey is showing signs of pain and lameness, and not putting weight on his back leg. I can only think that the lump is either pressing on something or something more sinister is going on within his leg/hip or back. His colour is still good and his eye is bright enough, but he's lethargic and refusing to eat. Though with pressure from the other dogs and Jamie he did eat a chicken thigh and I was then able to get some medication into him.
We now have no option but to see what tomorrow brings and take it from there ...