My horse has mole behind her ear. I have been keeping an out on it. It seemed to show up out of nowhere. I am worried it could be cancer..it doesn't hurt and it's hard and has no hair on it but she has hair around it. Thought it might have been her fly mask..we got a new one with fleece around it and the lump hasn't subsided...do you think I should get it checked? She's a black and white paint and I was told paints were prone to moles...don't know if it's time to freak out or not.