Fear and grossness

My boy is pretty rough and tough and doesn't let much slow him down. I've seen him run full speed into a wall which knocked himself on his back, but he got back up without a tear and kept on going. But, if he sees a drop of blood, he is a total basket case and you can't calm him down till there is a band aid or something covering it up. He has cracked his head open 3 times already, one time resulting in a trip to the ER (first time) and he got the special glue stitches. After that, we used the liquid band aid at home and no issues. Anyway, my point behind it is that he is very freaked out by blood.
So, Saturday night he was playing with a tiny light up snow globe that we got last week. It takes 3 of those tiny button batteries. Because of people playing with them on the displays, the light up feature didn't work. So he was playing with the batteries thinking if he twisted them around that it would finally work. He was warned multiple times to leave the batteries alone. He finally listened and took it out to put it on a shelf in his toy room. A few minutes later I heard him in the kitchen with my mom and she was talking in a very stern voice saying he needs to give them all to her immediately. I walk out and he says "don't tell mommy!!" Of course I get told. He was shoving those batteries up his nose because he thought it would make him look funny and make people laugh. Um, NO. So I took it from him, threw the batteries out and he lost his new snowglobe. That was dramatic but I didn't feel like it was good enough. Then it hit me. I came online and found some really nasty pictures of nose surgeries, like the blood and grossness during the surgery. I showed him a picture of that with the blood and told him that if he sticks things up his nose again, and it would get stuck, we would have to go to the hospital. And that they would have to cut his nose open like that to get it free. The look on his face was priceless and he swears he is never ever going to stick anything up his nose EVER again. Kind of cruel, but it got my point across. Shortly after showing him that, I got to searching a little more. I found another picture that was scary to find because it was of a 5 yr old that did exactly the same thing with those tiny batteries up the nose. They actually got stuck, and the battery acid ate through the nose. Apparently it can happen pretty quickly once that is stuck. We also talked about that and my point is very clear now I think. Today he mentioned those "disgusting pictures" again and promised yet again that he is never going to do something like that EVER again.