The rest of the day is rainy and damp, and Sadde reads and thinks about magic and eats deerthing meat and sleeps (unfortunately the night sky isn't clear enough for a good look at stars and moons or lack thereof). The next morning is sunny and warm—and damp but not wet—so they decide it's a good time to try to find their way back home. They eat, change, and pack their tent, then go, towards the river. It's the one landmark they know about.
They reach it and try to retrace their steps and fail, then try again and fail again, then it's time to eat. They set up their tent by the river, make another fire (they still have a bit of meat left which they eat but it's smart to do it anyway), eat, then try again. And fail. But that's alright, they can explore and try to find the place again.
A giant eight-eyed dinosaur thing tries to eat them once, and they destroy all of its internal organs.
It rains again but at night—the day is annoyingly shorter—the sky is clear enough to show constellations they've never seen before and two not terribly pretty moons.
It's warm during the day but there's rain and the rain sometimes is cold and in the evening it is cold without the fire but there's fire. They try looking for the place again the next day. And the next. And the next.
They run into other animals—comparatively small (i.e. about waist-high) brown fuzzy six-legged things that are reminiscent of a cross between a rabbit and an eggplant, various kinds of bugs (Sadde murders the huge not-mosquitoes with a vengeance after the first time they get stung), things that are kinda like fish and kinda like eels and kinda like neither and really huge, lizards without a discernible head about as tall as them, carnivorous lizards with discernible heads that don't actually bother them—and as time passes decide they can't really only survive on deerthings. Probably.
But berries and fruits and plants are still probably dangerous.
That's the next thing they'll try to learn—how to survive poisons. Their thing is making their body be that way instead of some other way, it's all biokinesis, really, healing is just another application of it. It does mean they learn it much slower than other mages would (on Earth, he's not on Earth right now, is he, how does that even work), but they do try to learn it.
They have a watch. They know they've turned seventeen, by keeping track of days according to their watch, but what sense does that even make when they're probably far enough away that relativity should matter?
They're confident they can deal with poisons after seven months, ten days, and thirteen hours. They've been eating plants for a while by then. Their clothes are in tatters, their knife long gone, their tent barely more than a fond memory. It's damp. And warm. It could've been damp and cold, that'd be worse—and sometimes it is, actually, but there isn't much seasonal variation there, or perhaps the year is just really really long.
And they can't find the goddamned cave.
They turn eighteen.
And two months, five days, and four hours after that—
