What does 冒了出来 mean here?
1 冒出来 literally means to pop up, to suddenly appear. In this context, it means to become popular. For example：最近几年冒出来了很多互联网公司，他们的增长速度让人吃惊。

2 回归  here it  means come back to former situation. For example: 他们的心情最终会回归平静的。