Blossom, about 7 has a change in skin color under fur on one side. Seems more noticeable lately. Not real good exercise tolerance, walks slow but that is not new, sometimes puffs but that is not new, has had some bouts of bilious vomiting over the last year or so. What could cause this change. Had her on silicea a few months, stopped and now thuja and will alternate. For the vomit I gave her a dose of nux about a month ago