Icarus had a cyst once. It was huge, it took up his whole shoulder and more. It appeared next to his injury is because the injury swelled a bit and put pressure on the sebaceous gland, kind of blocking it. This in turn caused a build up of sebum and oils within the skin. After a few weeks, I finally popped it, and yuck, it was really gross. Lol.

Is it a tiny bump? I'm not sure what they are called, but there are bumps that dogs get sometimes. They look like moles. My friend took her cocker spaniel to the vet about it, and she was told that they are nothing to worry about.

Hope it's not serious!