Looking around I found messy geometry around the V of the collar, which I gonna fix right now ... it's a good thing cuz it show ya how to spot it (cuz it ain't obvious) and how to fix it. Set at polygon, I select at the V:

And that's not good cuz the selection don't show all four edges picked ... the whole geometry in the V of the front of collar looks kinda like an unholy mess, all those lines coming from one vertex at the top, so let's fix it. Remove Meshsmooth modifier. Delete all the polys inside the V like so (two views, both looking at the front, the first one a little below, the second a little above):

Here you can use target weld to join the three vertices with their match below: