My puppy is 6 & 1/2 weeks old. We put a flea collar on her last night that specified "Do not use on puppies younger than 6 weeks". She has not eaten and has vomited quite a few times since then. She is taking in some water. We removed the collar at 6:30 am this morning, which was about 16 hrs. ago. She seems better after drinking the water but about an hour later she throws it up along with a white foamy substance. The last time she threw up was about 8:30 pm and it was yellow.
What can I do?