Best way to temporarly increase agility and flexibility of your freaking mouth in 5 days?

Best way to temporarly increase agility and flexibility of your freaking mouth in 5 days? A few days ago. My medical school interview shook my absolute core because I couldn't deliver a sentence without a block and facial spasms. Thankfully, I have 3 more interviews for elite medical schools coming up. Honestly, I can't help but laugh today. I have another golden opportunity but don't know man. I can't deliver like my first interview. I know this sounds ridiculous but what is the absolute and extreme way to prepare for the next 5 days that gives the best chance of fluent interview? My stutter is moderate in day to day life but severe in high stakes situation like interview as proved this week.