Here's why:
* "Otherwise" is an adverb. It modifies a verb, adjective, or another adverb.
* Adverbs at the beginning of a sentence don't typically require commas.
Example:
* Correct: Otherwise, we'll be late.
* Incorrect: Otherwise, we'll be late.
Exceptions:
* If "otherwise" introduces a contrasting or parenthetical statement, you might use a comma:
* Example: I'm happy to help, otherwise, I wouldn't have come.
* If "otherwise" is followed by a list or series, you might use a comma:
* Example: Otherwise, we can choose from the following options: A, B, or C.
It's generally best to avoid putting a comma after "otherwise" unless the sentence structure clearly demands it.