Pics would be good. If it's his stomach that keeps coming out like that, you'd be better off returning him to the store, as there may not be anything you can do for that. If it's his tongue, there's the possibility that he has some sort of oral infection causing his tongue to swell? If that's the case you might want to try some sort of antibacterial treatment. I can't tell without a picture or anything though.

Also, if he's having a hard time actually catching his crickets, it's a good idea to remove their hind legs. It keeps them from crawling away to quickly and also it makes them easier to swallow.

Keep us updated and hope your little guy improves!