Here s the thing.

I change diff color from blue to white and the black line stays only in shadowed places and disappears on lighted surfaces. If my eyes don't lie to me.

blue:

white:

Like so, I don't feel at all that the characters has a moustache. It looks like a shadow (a bit excessive maybe)

The problem is I can't use this pink face and It will take too long to improve the textures. (((