Guard bald spots..?

[Violence6884]

[Had to go at it from scratch since I isolated the issue a bit more, apologies to those trying to help me]

 

These steel helmets http://elderscrolls.wikia.com/wiki/Steel_Helmet_(Skyrim)(Hopefully only these) make the PC and NPCs wearing them partly bald. In the case of female NPCs it adds a head ornament on top of making them grow a bald spot, which means a clothing or armour mod I'm using messed things up.

 

In any case these helmets appear normal on the ground and in the inventory and so far they are the only helmets affected. Their armour value and other properties are fine too, so I assume I simply need to somehow restore their model on the characters, their appearance when equipped... Which I have no idea how to do or where to find the appropriate files, nor where to place them in the game folder. Verifying the game files through Steam to restore these specific files will probably destroy my heavily modded installation so I'd like to avoid that.

 

So... Yeah. Any help would be appreciated. In the meantime I'll try to see if indeed one of my ~80 clothes and armour mods is the culprit. Perhaps removing that will fix it. FML.

 

Edit - It was a mod called [NSut] Mei Dress, the included hair pin is what's messing with that particular helmet. I'd really like to keep the mod so any suggestions are welcome.