"But why do they hurt? And you, Doctor..." There is a sudden softness in her voice, hint of a smile on her face even as tears of pain stream from her eyes. She gasps, mouth twisting into a rabid grimace. "No! I will not allow it!" She smiles at him, a smile that hints at knowledge, power, a dangerous being under the surface happiness. "For you, Doctor, I will change time. Consider it...a gift from the universe." And with that, though few notice, fates are sealed, and time takes a new course.
She's smarter, that's the first thing she notices. The Doctor is spouting his usual technobabble, something she's tried and failed repeatedly to understand. Then suddenly something...snaps. The words tumble out of her mouth before she thinks to stop them.
"But that'd create a feedback loop, temporarily fry your brain, you wouldn't be able to get out! Couldn't you rig the sonic as a remote detonator?"
He stares at her, wide eyed, before visibly snapping himself back,
"Rose Tyler, you are a genius!"
She can still see the confusion and worry in his eyes, but before long it's running and explosions and saving a world, and she pushes it to the back of her mind.
Then there's the soothing hum of the TARDIS gradually becoming a song, a multi-layered song full of Time and Knowledge and the Universe, heartbreakingly beautiful, and so comforting. Soon she can no longer sleep without it, and eventually it follows her, fading back to a soothing hum with distance, but always there.
The colors. She can see them, strands of color, twisting and turning, and it reminds her of something she can't quite remember. She looks down at her own hands and sees them, gold and vibrant, she looks at the Doctor and sees silver-blue, and around the two of them they are blurred, twisted and tangled, and moving.
And everything seems so much brighter, she can taste and feel and see and smell, like cotton wool pulled away from her body.
She hardly ever sleeps now, preferring to sneak away into the library and read.
She hides it from the Doctor of course, not wanting to worry him. She's fine. Absolutely fine.
It was all back to normal, running for their lives, saving worlds, being legends.