Yes I think a vet check will be sensible and Rosella is right, I hated cats until my first mate Kocka walked i to my life......now am even known in my art group as the cat lady
He sounds just hungry and am sure the assistant was just trying to help but doesnt have enough knowledge really.
The other thing is, that if he did have worms, they would be making him hungry as they would be stealling his food from inside. The vets do a spot on wormer that they could sell you, about £6 at my vets I think. I dont worm my cats , only once a year at their vet check but know many do it regularily.
Yes you are right both worms and fleas can come from escapades with the wild life LOL, I have two that spend their life hunting,,,,,,,,,,,,,,this year has been bad for that I am pleased to say
Good luck tomorrow,,,,,,,,,,,,,,,,,,,,,,,and you are not stupid, you have done the best you could for Scampi and now you have found Purrs we can help you by answering any questions you have, or not