This is a re-post of my answer regarding lumps and bumps on dogs. Bumps
and lumps are common to occur in dogs. Small bumps called papules or
large bumps called nodules can develop in the skin. These lumps can be
felt under or within the skin. The causes could be from something
simple as an allergic reaction, or to a more serious disease such as
skin cancer. If the lump is growing fast, painful or warm to touch,
bleeding, shape is irregular and is well attached to the skin, it
should be evaluated by a vet the soonest possible time. Lumps should be
physically diagnose a your vet and may also take a sample for
laboratory test to determine what causes this lumps so that the proper
treatment and medication can be given to your dog. Take care and good
luck.