Hi Julie, Oftentimes a Berner can get a sebaceous cyst that is about the size of a marble, the vet will open it and brown-cream coloured curds come out of it. The vet may choose to put the dog on antibiotics. If the vet is in any doubt about it he will needle biopsy it first and have that analysed. If the lump feels "rooted" he may recommend surgical excision and again have that analysed. Go carefully over him and see if you can find any more lumps and bumps for the vet to examine.
One step at a time:-) Rose T.
