> since then he has been starved then fed chicken and rice
Four months is very young to 'starve' - how many meals did he miss? Although most adult dogs can miss a meal it's not always wise to starve youngsters and they can get dehydrated pretty quickly. Has he still been drinking?
At this age I'd always err on the side of caution and more than one episode of sickness, or a flat 'not himself' pup, would be a vet visit for me. Let us know how you get on
Incidentally, was he ill after worming?