You'll need to keep his humidity at 80%. Try covering 3/4 of the top screen with plexiglass, glass, Saran Wrap, or foil with the edges folded up. Of course, be careful not to put any heat lamp on top of the plexiglass or Saran and if using glass, lift the lamp up off the glass a few inches.
Babies digest best with daytime temps of 80-82'F.
Try using cut earthworms/night crawlers instead of red worms. When red worms are cut or injured they secrete a foul mucous so many frogs do not like them. Try tong feeding and wiggle or scoot the worm pieces in front of him.
What does your little guy look like?