This is just a quick post to put up a photo of a lump that I found on our guinea pig, Bunny, today. Hoping that some wise people on a gp forum can give me an opinion or two.
The 'hole' in the middle is where a nasty bit of stuff fell off as I parted his fur. You can feel a lump under his skin around the hole - about 2cm across.
This is what fell off the middle of the lump.