What Causes Sudden Stiffness In Jaw Muscles?

Hello, I thought I would ask thIs question to get your opinion as well as to share with other readers. I was shaving the neck of my husband while he was kneeled down on his knees, when he stood up he was looking in the mirror and what appeared to look like a dimple formed in his left cheek. He could feel his jaw tighten. He wouldn't speak. I'm not sure if he couldn't or was just so scared that he didn't. It lasted only seconds. What is your opinion of what happened to him.