Its just a mole my pitbull has one its basically like a birth mark, my one has it behinds its front right leg
My Pit Bull Has A Cyst Or Mole Looking Growth On Her Leg. What Could It Be? It Is The Size Of A Nickel.
It's most likely a cyst, but just to make sure that it isn't cancerous, I would take her to the vet. Especially if it's changing colors. Hope this helps, good luck.