This question came up for me when I made the decision to self-publish. The short answer is yes! absolutely.
Of course, we all look for ways to minimize our expenses and get our book into the market place as quickly as possible. But having a professional editor look over your work is NOT the place to cut corners. The book market is very competitive. And although everyone says you can't judge a book by its cover, everyone does it. And then they judge it by the words, and the design, and whether it has an ISBN, etc. I recently had a bookstore salesperson say that my book did not "look self-published..."
However...that simply tells me that if I were only competing with self-published books I would be ahead of the competition is some respects, but I am not. I am competing with every picture book on the market. And the vast majority have been rigorously edited by publishing houses before they are printed.
As you begin your search for an editor, look for someone with specific qualifications in children's books. I found a number of "copy" editors who could look at the book with a very quick turn around for a very low fee. This group would do a fine job if I was simply looking for someone to check for spelling mistakes and correct grammar.
What I needed was someone to look carefully at the storyline, meter, and best use of words. And then analyze how the text related to the artwork. I needed a fresh perspective on the art and someone who could look at continuity of character, balance, composition, text placement, etc.
I found two editors that I feel would do a great job with your book,Linda Zuckerman and Nora Cohen. I recommend both of them. They both have long waiting lists, but again this is not a step you can afford to skip. Polish up your book the best you can, send it to everyone you know for their feedback, and then find a professional editor like Nora or Linda.
Be prepared to spend between $300-$700 for professional children's book editing.