Yeah, I know, I've got the issue right in front of me. But it still doesn't make sense to me why the rest of her pajamas didn't catch fire. And the first instinct of someone who's clothing is on fire is to get that clothing off as fast as they can.
Johnny likely extinguished the flames as soon as he realized he burned her. He has such control over his flames he shouldn't have burned her in first place if you ask me.