I don't know... It isn't really necessary, since she's already knows about his mom. Besides, she could think that they are from the lashings that were too deep for her to properly heal.
Wait wait wait this is just a question then in the heroes of Olympus books why have we not heard of any scars on percy I'm just saying and plus some of it's from a car crash I'm going to get to the later on
I keep coming back to it trying to post something, I do but I just can't manage to do anything.... Sorry. I didn't want to say that I couldn't continue in case it was just writer's block and I managed to get something... but it looks like it is that way.