Side Effect of Ultherapy? Difficulty Swallowing?

The muscles that control swallowing are deeper than the 4.5mm depth of penetration of the ultrasound energy and the pharyngeal mucosa of the throat is much deeper. I have never heard of problems swallowing after ultherapy.  If someone has Botox injections in the neck there have been rare reported cases of difficulty swallowing. 

Anyone having unusual symptoms should discuss it with their doctor.

The information provided in Dr. Shelton's answer is for educational purposes only and is not intended to constitute medical advice.  The information provided should not be relied upon as a substitute for consultations with a qualified health professional who may be familiar with your individual medical needs.

There may be slight redness for up to an hour or so following the treatment, and a small percentage of patients may have slight swelling, tingling or tenderness to touch, but these are mild and temporary in nature. There is always the possibility for other less common post-procedural effects, but difficulty swallowing is not a symptom that has been widely reported. I do not believe the throat inflammation is related to the Ultherapy treatment. 

I have done over 100 Ultherapy cases and I have not had any complaints like yours and I am not aware of any similar complaints from the thousands of cases done across the world.  It is pretty much impossible for the Ultherapy to be the cause of your problem as the ultrasound energy is precisely focused at specific depths under the surface of the skin.  The energy doesn't come close to the inside of your throat or to the muscles that help you swallow.  If your ENT sees inflammation in your throat, the likely cause is reflux of acid.