Kids scrapes

This morning my son wiped out on his scooter. He scraped his wrist and his elbow. I cleaned the scrapes out with cool water and put bandaids on them. He is now at a friends house for the weekend and my grandma mentions to me “I hope you put polysporn on so he doesn’t contract flesh eating disease 😰” now I’m like freaking out because we did not put polysporn on and I didn’t even think of infections. Plus once those bandaids were on there was no way he was letting me anywhere near his scrapes. What are the chances of contracting a bad infection?