Do you have any substrate on the bottom of his cage or is it bare? you should post some pictures of what you have set up now.
A quick fix would be to add a drainage table that the terrarium sits on. Most people make their own tables out of some 2x4s with a large but shallow bin that the water...
shes super cute. Mine ate like a beast when I first got him as well. they tend to eat quite a bit when they are in their first year to help with their growth.