Welcome to the forum. You were absolutely right to be proactive. As you continue on your journey, you will find that if you can stay ahead of the game -- writing down questions for doctors, working hard on your daily intake, etc -- can make a huge difference to your level of comfort.

The need for a PEG may be somewhat of a shock, but it will make it way easier for you to reach your intake goals and stay hydrated. By the middle of the third week of radiation, you may find it difficult to swallow because of the pain and the swelling. That's when the PEG will be a blessing.

Have you been given swallowing exercises to do? Please do these every day. Swallowing muscles will become atrophied if they are not used even for a month. Maintain your swallowing ability is key to preventing aspiration (and the related problems) further down the road. Even doing dry swallows throughout the day will help.

Do come back and update us from time to time. All the best!