Congratulations on your promotion. See if they care about your stutter then they wouldn't have promoted you. Believe me people don't care. Don't be ashamed of your stutter. For me my stutter gets so much better when iam comfortable and secure with my self. Never avoid talking, beacuse when you avoid talking and when you start talking again it will just make you more nervous. If a situation make you nervous just do it again and again and after a few times you will be relaxed. What makes you so nervous in your situation right now?