按钮上是否可以包含:after伪元素?

我有一个按钮，在:hover 上，我想显示一个after元素.但是我看不到.

I have a button and on a :hover I would like an after element to show. But I can't see it. Is it possible to have an :after element on a button?

.button {
  cursor: pointer;
  height: 30px;
}

.button-primary {
  border: none;
}

.button-primary:hover:after {
  display: block;
  position: relative;
  top: 3px;
  right: 3px;
  width: 100px;
  height: 5px;
}

<button class="button button-primary">My button</button>