I've noticed recently that my dog has these wart like bumps. One on the top of his head, it almost looked like a tick at first, doesn't bother him at all, just looks yuckie. Then today while trimming his nails I noticed another one on the inside of his back leg, just above his knee. Its about the size of a dime and sticks up about an inch. Are these sort of growths normal in a dog his age? He seems very loppy and skitish lately which is not normal. I'm not sure if I should take him in or not.