What should the inside of the mouth look like ?

[GregWolley]

I just fed my 1,5 year old superworms for the first time in over a year. Had come out to bask after what appeared to be the beginning of winter brumaation. Normally eats canned food, veggies and dubias. Shortly after it ate about 8 - 3/4 inch worms, it began gaping it’s mouth all the way open for the first time I’ve ever seen. I know all the listed reasons when this could occur: thermoregulation, territoriality, etc. none if those apply here. Also read about extremely rare cases of the worms biting from the inside. I saw a tiny bubble on the edge of its mouth, and his mouth looked mucusy inside. He was breathing normally. What should the inside of a normal mouth look like? Wonder if should bring him in to get checked. Most posts say “don’t be concerned”.