This happened to my wife too.
She says "Hey, it kind of hurts here, can you take a look?"
I said "sure!"
Then I was like
And then like
"Um, it looks . . . ok . . . but there is a hole . . . ."
We did visit the Dr. though and he cleaned it up. It healed fine and fairly quickly from the inside out when cared for per doctors orders.
Fortunately it did not happen with the second C-section. I've heard its fairly common though.