I ran into this one a few months ago while unsuccessfully researching someone else's question. It was online, in color. A woman was being guided by a man who she'd hired, heading to the location of a witch in the forest. I believe the way to the witch's residence was hidden by magic so that you wouldn't notice it until you were on top of it. I think it was inside a large hole, or pit, in the ground. After introducing herself to the witch, the woman explained that she'd woken up one morning with magical runes around her neck, and was seeking to have them removed. She has no idea who might have done it, or why.
The witch, who was dressed in kind of ragged robes, and had a large stag's head for a mask (or maybe it was her head... in the bit I read, it never was removed), takes a look at the curse, expanding it in a horizontal plane, and explains that it is old magic, powerful magic, with a trap laid into it that would kill the woman if removed improperly but would also just eventually kill her, and that the witch did not know how to remove it. However, she had an idea of where to look, and decides to accompany the woman since it was a chance to see this old magic in use.
The style was kind of rounded, not manga-style, not realistic, but also not terribly cartoony.