What Causes Shrillness Of Voice After Removing Nodule From Vocal Cords?

I feel my son (5years)is not benefiting from salt. Concerned he is becoming anxious, knows he is being tested and voice becoming more high pitched. Nodule removed from vocal cords about a year ago. Child has appointment each week. Imy child is extremely bright and clued in and salt watching his walk, speech etc. normal voice deep and hoarse and does occasionally speech in high pitched tone to me but I call it his performance voice when he becomes in a test situation. Runs on tippy toes also attending physio. My son born at 26weeks so small developmental problems but due to all appointments becoming self conscious but good concentration and excellent at school and extremely social but feel definitely confidence being diminished. Want to stop appointments as negative impact outweighing the benefits