Could you change your own tongue piercing yourself?

Depends on how old it is. If you've never had it changed by a pro before though, its a good idea. They can easure and fit you with the right bar. If you use one thats too long, it can make gum/enamel erosion even worse and youre more likely to bite it. If its too short, it can cause swelling or other problems. If its not 2-3 months old yet, definitely go have a pro switch it out :)