Oh those teething puppies.You can help ease the discomfort with some very simple home made ideas. 
Take the rope toy, soak in broth and freeze. If you don't have a rope toy, take a small towel, soak it,squeeze out excess water, tie in a knot so he has something to chew on and freeze.
Fill a Kong with broth/kibble/carrot pieces/cheese pieces/etc and freeze (remember to plug the hole at the bottom with a piece of freeze dried liver or something else). - Try a couple of broth ice cubes!
Freeze large carrots - use with supervision though as a large chunk can break off.

All these options should be offered with common sense and supervision.