OK, so the crickets should be no longer than the distance between the frogs eyes.

You can also try earth worms, just cut them down to bite size pieces or slightly larger.

You can put Neosporin WITH OUT PAIN KILLER (usually labeled original) but read the label, on any open wounds.
If he will eat, which might take a few days, put calcium powder on some crickets. He will need this a few times a week if kept.

Also get some pedialite unflavored (small bottle will go a long way), Unflavored pedialite looks like water and has barely any taste. Drop this in warm water (mid-70s or room temp) at a 10/1 ratio (10 water, 1 pedialite, so like...10 ounces of water, one ounce of pedialite) and mix it in, then give the frog a bath for 10 minutes to let it soak in the nutrients. This will get some needed nutrients back into him while healing.

Good luck and ask questions if you need some help.