Is the bump line going down the center of the forehead just a usual detail of ToTs kirks or is this an actual issue? I’ve seen it on other copies, but it’s been bothering me lately
I’ve noticed that on a few I’ve done. The mask was probably stored folded down the middle for a while before you got it. Try turning it inside out for a few days stuffed.
It’s the infamous “Crease” that was on the Hero. It’s just very very subtle on screen. You can only see it under certain lighting conditions.
I don’t think it’s any kind of crease other than a byproduct of how they ship them. They fold them and throw them in those flat rate boxes and it’s not really ideal. Some massaging and a hair dryer may take it out
I’m sure it can be exaggerated by the shipment, but the crease is most certainly in this version of the creep/shat sculpt.
It’s intentional and part of the sculpt. The Nightowl Shat and Creep (the source masks for the ToTS) have the crease as well. In some parts of H1 the crease that was the inspiration for the one on the Creep is visible (due to Nick Castle folding the mask up in his back pocket probably).
It’s visible on the lobby card shot of the hero with Castle by the station wagon, Justin doesn’t have it on the newer Creeps though, not sure if the shat still has it
Part of the sculpt 
this pic?
That’s the one