My DS got burned a few years ago - I was scared that he'd carry all his scars for life, but gladly only a couple remain, the rest have vanished.
While they healed though, there was a long period where they were visible and DS was self-conscious about them, and I felt sad to a point that DS was not 'perfect' as he had been before the accident. The guilt I felt too was crushing.
Another MNer was so super supportive and her perspective really helped me wrt scars. She shared with me that for her and her DC, the scarred skin is as much our child as the non-scarred skin, we have to love the scars too, because they are part of our child and he/she is lovable as they are.
We did joke about inventing stories about wrestling with piranhas or peckish sharks, until DS laughed and pointed out the being burnt was 'bad enough'
I think if we can teach our DC that it's OK to have scars if we have them and that we are loveable with them, then it's easier for our DC to be more relaxed about saying 'oh yeah, I got bitten/burnt/was in a car crash or was born like it.
The main thing for me was being taught by my parents that for whatever reason, I was not 'good/slim/loveable/whatever enough' I would not wish that on my DS. He's good enough as he is.