This is not an easy question to answer. As a writer, I would say yes. Follow up is important in keeping that connection between you and the potential reviewer. It can be very easy for a reviewer to forget about your book or even have posted the review and forgotten to notify you. More than likely it was not done on purpose and contacting them is a great way to remind them. Now that being said… How you follow up can make a big difference in how they respond.
Believe it or not, some writers can be downright rude or harassing when following up with a reviewer. One writer sent me a message a few weeks after sending his novel to me asking when he should expect me to post a review. The rudeness came when he said if I didn’t have time I should have been more honest with him. I have to say that after I informed him of my husband having been in the hospital he was more apologetic. I had another writer contact me on a weekly basis asking when I would have the review for his book done. To be honest, that became annoying as my life did not revolve around reading and reviewing books. His book fell to the bottom of the pile. That is not how you get your books reviewed.
Keep in mind that the vast majority of reviewers are not getting paid to review books. They are doing it because they love to read and want to help authors out. That means they have other obligations and their own life. Sadly, many reviewers have shut down because they cannot handle working with demanding authors. That is one reason the follow-up question is not so clear-cut. When does one move from being professionally networking to harassing?
So back to the question at hand. Do you follow up with a reviewer? It is not a bad idea to do it as long as it is done politely and with respect. Approach the reviewer humbly. Ask them if they have had time to read your book and if they need anything additional from you. Have someone else read your message to ensure you are not inadvertently coming off as rude.
Also, keep in mind holidays. You might send a follow up message during this time, but do not expect a reply until the holidays are over. The truth is that you might want to wait until everything has calmed down and then make contact so you are not adding any stress to those days. This I say as a reviewer. Stressing a reviewer out or ticking them off will not get your book reviewed or get a good review if you’re lucky they even look at it.
Before following up, think about the timing, how you word it, and how you would react if you received it with all going on in your life. Being considerate can only help your cause.