Last year our dog Tech (not pronounced TESH, or TEK, pronounce the ch like in cherry) developed a cyst on her side.It grew, got hard, and she lost all the hair on it. It was loose with the skin, and never attached to the muscle so we didn't worry. It went away, the hair grew back.
Well about a month ago it came back - this time however it ruptured. I said not to worry, the fluid would leak out, it would heal, the hair would regrow. Tom however decided she needed to see the Vet.
Last Wednesday the cyst was removed.