* Eastern Spotted Skunk: This is a smaller species of skunk, but it's still called an Eastern Spotted Skunk, not a "baby skunk" or something similar.
* Striped Skunk: This is a larger species of skunk, but even young ones are still called Striped Skunks.
If you're talking about a baby skunk, the term "kit" is commonly used.
So, if you're referring to a young skunk, you could call it a "kit." If you're talking about a small species of skunk, you would simply refer to it by its species name.