So Today, I Was Playing With My Friends On The

So today, I was playing with my friends on the recess equipment
It felt like something had poked me on the leg
I checked and nothing was there
And then during P.E, it was red, but didn't hurt
And after that, it was back to normal
-It still doesn't hurt
-it isn't red anymore
-and I can't find any cuts, or spots where it was poked
-My leg during P.E was also getting rubbed a lot
My parents say it's nothing.
But I don't know
Can you please help me