I understand how that can happen, I totally do, but in a serialized story, you start to see the strings, if you know what I mean. The more you see it, the less believable it becomes because at some point, even though they're never related to each other, various characters make the same mistake, and every time the author needs a new excuse as to why they're not going to the doctor.
As for the stings, I've personally always known about their danger, how an allergic reaction can kill you, not sure how widespread it is depending on where you live but it's common knowledge for me, so it feels a bit cheap to have this guy completely ignore Dr Goto.
You need to accept some stuff when you read a story, but I'm startng to see the pattern a bit too much now.