My son has an intense stutter, advice please.

My son has an intense stutter, advice please. My son is a couple weeks off four years old. He has had a stutter for as long as I can think but nothing out of the ordinary for a developing kid. Until the last week. Now he has some really intense episodes where he clenches his fists and his whole upper body, sometimes it's like he is trying to turn into the Hulk while trying to get words out. I am not 100% sure he is aware of it yet. The intensity and frequency vary. We want to take him to the doctor but we are in a strick lockdown which means emergencies only. Is this common? What should I be looking for? Any advice or reading recommendations or information is greatly appreciated.