nope, no deworming untill a fecal is done..
you need different dewormers for different types of worms and all kinds of worms can case pot belly look, it could be any number of parisites...without knwoing which one you have NO idea if the dewormer you have is going to work...
and by continually deworming without knowing if its an effective dewormer for the types of parisities he might have picked up your overloading your dog with chemcials it might not even need...
it woudl be like giving you antibiotics because you MIGHT have been exposd to a virus...you not only might not need the anitbiotics, but they may be the wrong antibiotics for the virus you might have picked up...
dont guess...keep an eye on him, if he starts to show symptoms (or in about 2 weeks) get a fecal done and go from there...