My blue merle smooth collie has started foaming at the mouth when she eats.   She gives the impression she has lost her sense of smell and finds it difficult to pick things up with the tip of her snout end.  The vet says she must have a pain somewhere and gave her ear drops.  I don't have any faith in vets for my animals the same as I don't have faith in my doctors for me or my husband.  If it wasn't for this forum I wouldn't have had her other condition recognized.
Please help me again.

Can you change vets? I would be wanting her mouth checked out as clearly something isnt right and foaming at thw mouth im not sure how they linked that to ears?

Teeth - gums?   Second opinion?   I have no idea how ears and mouth would be linked with this.   Have you checked the roof of her mouth - there could be something caught up there.

https://en.m.wikipedia.org/wiki/Masticatory_muscle_myositis I know this is uncommon and not sure if  it's possible to have a milder form but might be worth co seeing as some of her symptoms seem to match

Thank you all for your replies. I will go to another vet and ask if they will do a second opinion for me.  After reading your replies maybe she has something stuck in her throat. She takes Thyron for her thyroid problem.  She always took it willingly twice a day but is reluctant now.

I would definitely get another vet to look at your dog.