i have a little girl yorkie she is 12 weeks old.....i just started to notice that she is getting little bumps on her neck.....you cant really see them....but some of them have turned yellow and scaly.....i am not sure what it could be.....she has been on the same dog food since she was 8 weeks old havent changed anything with her.....we also have a boy yorkie and he has none of this? HELP!