Kids teething?

You could try getting the corner of a clean washcloth damp and throwing it in the freezer for a few minutes. He might be willing to chew on that. If he still drinks a bottle you could put the bottle nipple in the freezer for a few minutes to get it really cold and then put it on a bottle of cool water. use mesh feeder with frozen bananas, mangoes, or other frozen fruit to help soothe painful gum's large refrigerated or frozen pieces of carrot or celery, cut too large to place entirely in the mouth

It's been a while since mine were babies, they're in their twenties now. Popsicles or rib whiskey on the gums are the only two that I ever tried. The Popsicles worked better than the whiskey believe it or not.