My 7 year old silky terrier, female, has a quarter size black flaky spot on her stomach. Today i just noticed another black spot about the size of a dime on her inner thigh. They are slightly raised and when you scratch off the flaky part its red under and occasional will bleed easily. The flaky part comes back even if you scratch it off. is this skin cancer or any suggestions on what it could be? do i need to take her to the vet?