I think that teens vape because of social media, Social medical has been proven to trigger anxiety or depression, On social media they not only see other people vaping without warnings, They also may vape to cope, Something that can be done to help is taking down pictures or videos of young adults vaping and showing the long term effects
Try chewing some gum, of your choice, don't use mouthwash for a bit (the alcohol can make your mouth drier) reduce your caffeine intake, stay away from caffeinated drinks like coffee, and even soda.