Is opening and closing of the mouth for my white dumpy tree frog normal?

Question

2 year old white dumpy tree frog started yesterday to open and close his mouth allot.

Answer 1

What is his set-up like? Is he getting enough humidity? When was he last fed, and what did he eat?

Answer 2

Could be shedding.  Frogs do it to loosen the skin around their faces.  It could also be that the tank is too warm.  Make sure it's only 85ish in your hot spot.