This has been a prompt from Tumblr and I quite like how it turned out. It's actually my first fanfic in a few months I think so maybe leave a review? Anyway, enjoy!
Everything would be alright. Just a few weeks, a month at maximum. No need to panic.
But it was always easier said than done. Pepper knew she had to make the best of the situation. Maybe it had been a good idea to take a few days off after all.
The first few days, sleep hasn't been a friend of hers. She had barely spent time in bed, almost as little has Tony had after the events of New York. It didn't take him long to notice and soon enough they had started to stay up at night together: he tinkering in the workshop, she keeping him company while reading a book or papers for the company. Tony thought it was because she had nightmares about the events, about Extremis. It wasn't exactly a wrong assumption, but rather would she lose control over herself more quickly, giving Extremis the chance to take over her.
Self-control had always been something she had been good at, Pepper had been proud of it. But with her new powers she had found it harder and harder to control her temperament. It had been a week after the incident that she had decided to talk to Tony about it, knowing he would understand her.
They talked for hours; he would listen while Pepper explained her problems, her worries, her fears. And all the emotions had triggered Extremis as well. She hated herself for it, for being so weak and letting it win. Even when Tony told her differently, saying she was strong because she didn't let it destroy her, Pepper just couldn't believe him.
She had asked JARVIS for techniques to relax, anything that would her help to stay calm, and in the end she had tried it all.
That it would be a simple thing that would keep her at bay was quite ridiculous. She tried it for sleeping at first: when she would go to bed, she made a mental list of all the things that made her happy. It wasn't always the same, every night new things appeared. It calmed her, made her smile and eventually made her fall asleep. No more nightmares. Good.
It became her thing, listing things that calmed her to stay calm, controlling Extremis inside her body. While at first it seemed to be the only thing that helped her in her daily life, it came much easier the longer she practiced it.
And one day, three weeks later, Pepper realized she didn't need it anymore. Extremis couldn't get the best of her, she knew she was stronger, the last weeks had proved it to her. Eventually Pepper even learned to take advantage of it. Who could say they were a real human heater?
Yes, Pepper Potts was a hot mess, but had learned to life with it.