Question: how to change your snapchat bitmoji expression?
Answer: In the Snapchat app, tap on your Bitmoji avatar in the top-left corner of the camera screen.
Under 'Bitmoji,' tap 'Select Selfie'
Scroll down to see all the Selfies, then tap to choose your Bitmoji Selfie.
Tap 'Done' on the bottom to save your changes.