Lel EVOX question. I have a neck seam bad with this head. I am wearing the right body/head combo. I have a seam with all of my skins for this head. I tried the Izzie's neck fixer and that does not even fix it.
So I am thinking maybe its a setting in the hud, materials, or something??
here it is with izzies demo 
I have not had neck seam problems in years!
Have a look at the materials (shininess) settings. I had the same problem with my LAQ head. Until I went full latex, that is.
are you wearing the latest update of your body?
if you bom, make sure it is all bom
even body
and rearrange your layers help too, body below head
I am wearing the Maitreya Mesh Body - Lara V5.3, in the above picture, I am actually not even wearing a body/head combo (although they also look like this), Above is a BOM skin, all in one head/body together.
reorder your layers. show us your "worn" tab and what order
Wicca Merlin gave me a great tip for this issue (and Allegory) and it was to set the to play around with the neck settings on the body for Maitreya 5.3
I set to 0 and all was good