I would somewhat disagree with your vet about your Yorkie being able to see..lol My Yorkie-Poo had the hair flopping over the face, and other breeds have that naturally and can still see. But, I understand the guilt...and I know this problem well. lol
Brody was taken to a groomer by his former owner THE DAY I got him...he was 14 months old and had had long hair but they 'puppy cut' him.
The groomer did NOT trim his ear hair...ever...which was very long...but DID trim the top of his muzzle (nose hair) and tried to cut a visor. His hair was very fine, thin and silky with little to no 'body' and the visor hung down over his eyes and the muzzle hair made a 'fan' in front of his eyes. To make it worse, his muzzle hair grows straight back toward the top of his head...no natural part, like Mia has. I grew out Brody's muzzle hair for about 8 months before it got long enough to create a visble "V" looking like it might lay down on each side of his muzzle. I would 'slick' it down with water, and it would pop back up when it dried...lol He dropped the puppy hair on his head when the 'more body, slightly darker golden tan' hair came in. Today, I can 'slick' it down, or it may separate into a "V" on top of his muzzle, but it still does not lay down nice...like Mia's.
Mia, however, was cut VERY SHORT when I got her and her hair grew very fast, and laid down the whole time. Her muzzle is a little longer than Brody's, though. She also has fine, silky hair, but thicker than Brody's, and neither tangle hardly ever unless they get weed seeds, etc. caught and scratch to get them out or something.
If you want to grow him out, you may just have to 'arrrgggghhh' your way through this wicked growing phase...
