Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I am so sorry to hear about Harlow,...he is so young to be having these issues which leads me to believe that he may have genetic problems causing a suppressed immune system and other problems. It does appear that he may have an unstable disc in his neck which is very uncommon in such a young dog such as Harlow.
Since Harlow does have the anti ninflammatory aboard, there is nothing wrong with waiting until the MRI tomorrow....just do not let him jump on or off anything and carry him up and down stairs to help stabilize this disc.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, Dr. Loretta