The phrase "after a while even" is correct and usable in written English.
It can be used to indicate that something occurs or becomes true after a certain period of time, often implying a sense of surprise or unexpectedness.
Example: "After a while even the most patient person can lose their temper."
Alternatives: "eventually even" or "after some time even".
But after a while even he admitted that it was pouring.
And after a while even the thrilling, repeated enough times, can become numbing.
Through it all, Howe kept claiming that the team battled, but after a while, even his players ignored him.
After a while even the festive parade of outlandish costumes, among the show's more reliably entertaining diversions, begin to feel stale and overworked.
After a while, even her son, Jovan Wright, stopped asking about her. "She could have been cremated or buried somewhere, and we'd never know," Holmes said.
After a while even the zone around the Washington Monument got so crowded that people sat atop the rows of port-a-potties.
He staggers on for a while, even after being fatally shot multiple times by insurgent islanders, whose leader has saved his money to make silver bullets.
Little things like standing outside your classroom for a while even after all the kids have left will help to show that you are welcoming.
This does not mean that, eventually, a rising tide on Wall Street won't lift all the boats on Main Street -- or that those boats won't stay afloat for a while even after Wall Street runs dry.
He worked from Obama's former campaign office on Michigan Avenue in Chicago for a while, even after it was a dark, largely vacated and depressing shell of the former nerve center.
So when a 6-foot-5 quarterback, playing for a former N.F.L. head coach in a popular offensive system, sparkles the way Schaub did that season, the luster does not wear off for a while, even after an injury-related dip in his senior season.
