- abcesses can take a long time to come to a head - especially if given bute
- swelling or puffiness anywhere?
- heat anywhere?
- pulse in foot?
- standing awkward?
- shoes on or not?
- sore anywhere above the foot?
It sounds to me; very similar to what happened to Boo - turns out he had cysts in his navicular bone... I think xrays would be a good investment