Carlos is correct about the surface area for the frog's enclosure.

As for a swollen tongue. That can be caused from the frog biting its own tongue while feeding. If you are offering only crickets then that is only good as a staple, but is not a very nutritious diet even if you use supplements. Night Crawlers are far more nutritious and are easily digested.

If the tongue is swollen then it is possibly infected and would need antibiotic treatments from a Herp Vet. I'm not sure if a few antibiotic baths would treat an oral infection like this.