There's a dense forest to the far southeast that's hard to look at and impossible to resolve in her vision, but it's on the far horizon and it's hard to tell if that's enchantment or just the limitations of her eyesight at the distance of a hundred miles.

...Well, if she turns and looks at things similarly far away in the other direction...?

Less blurry. Could also be the fog, though.

Might, might not. She has a while. She heads for the dense forest.

As she gets closer she's more confident it's an enchantment. The forest is painful to look at; her eyes slide away. If she lets her attention wander she finds herself no longer flying directly at it.

If she overlays her eyes with an illusion of what it looks like when it looks like something does this effect go away?

It stops being painful to look at; she still notices herself veering away.

Well, that won't really help, then, but it tells her the effects are probably separate. Healing spells: dent the ache or no?

Yes, but it's like looking at the Sun; casting them makes the pain stop, but it'll start building up again immediately.

The trees here meet in a dense, interlocking canopy; she can't see the ground beneath them, even as she gets closer.

Too dense to fly? Too dense to hike?

Too dense to fly through the trees, probably; the undergrowth is much thinner.

As a test she ascends again to see if the headache comes back or is gone for good.

Nope; as soon as she is above the trees they are painful to look at.

She lands again, on a sturdy branch, and transforms and climbs down.

It's a beautiful forest. Far too tropical-looking for the climate of the continent, with flowers blooming everywhere in the undergrowth despite the fact they have no sun at all. The forest is infused with a shimmering silver light that seems to be coming from everywhere and nowhere.

Pretty. Loki only climbs to a few feet above the ground in Asgardian shape, and then decides not to trample the flowers. She can't go at a hundred miles an hour in such dense woods but she can weave between the trees, looking for civilization.

It's not civilization, but she sees someone only a few minutes later. Elven archers, bows drawn, racing through the trees (which seem to conveniently part for them, or maybe they know exactly where to step). They're silent and hard to see against the trees.

They all open fire on the source of the sound. There are more of them then she expected; at least thirty arrows fly in the space of a second.