My daughter had two hernias when she was born. Just above her tummy button, one above the other, with about a centimetre in between. Both about the size of your thumb nail. Basically her stomach muscles hadn't knitted together and two holes were left.
She had to have monthly hospital visits as they wanted to ensure clearly her stomach wall didn't rip, as literally her insides could have poked out , but they also wanted to balance the risk with waiting till she was bigger to operate, and when she was nine months they did operate.
They did it very well. They went in via her belly button and sewed them both from the inside, so that when she grew she would have no scars on her stomach. I was really impressed when the surgeon came out and told me.
She's 19 now and you can basically see a very tiny half moon round the top of her belly button if you know to look, otherwise you wouldn't know, it's like a white thread circling the top inner half of her belly button. It's very clever
It was a general aneasthetic, and yes it's terrifying when they go to sleep, I went down with her to the theatre, but a couple of hours later she was back up on the ward and once she had eaten and drunk (and I think maybe pooped), they let her go home that day, she then went back to have dressing off and be checked. All good.
Don't be concerned, they really know what they are doing and hernias in babies are very, very common.💐