I'm going to say this in the nicest way I can. Be patient. If people want to respond to your topic, they will. If they don't, then they don't. Bumping the topic until somebody responds is not allowed and it doesn't get you anywhere.
To be honest, why would you want to see them get stung? It does nothing to help the plot progress. The conversation was about bad luck. Petrie didn't believe in it, and what happens? Ducky and Spike arrive after being stung. That's all that's really needed. I honestly would not have wanted that scene in the movie because I don't think it would have added anything to the plot.
It's more than likely Petrie did not get stung when he fell, otherwise we would have heard him yell "Ouch" or something along those lines. When he flew out, he was yelling out of fear not pain.
In terms of injuries, I might be repeating this and if I am then I apologize, but Chomper bites Cera's tail in LBT 2. Yes, no scars or anything appear, but getting bitten by something that could have easily torn her tail off (excuse the graphic imagery) is far more severe than being stung by a wasp.