skin lump

Question
e have a 7 year old brown lab who has a 1 cm lump in the skin on his back. What could this be?

Answer
Could be a lot of things, even a cancer.  I would watch it very carefully, and if you see it is growing or more develop, get him to the vet.  Definitely point it out to the vet next visit.  Since none may be scheduled very soon, perhaps schedule one.