Depends on the length of the cut a little. You might get away with a pinprick or a nick, but probably not a longer cut.
A neat scar requires two clean edges of skin that are close together and allowed to heal.
There's a practice amongst some less than savory people of mounting two blades next to each other, a few mm to a cm apart, done exactly because if you cut the skin into ribbons it's incredibley difficult to stitch and the four skin edges will not be held together well. The injury is very likely to leave a nasty scar.
Multiple cuts in the same area will be a complete mess. You'd need a surgeon's precision to open the wound time after time along the same line to prevent a ribboning effect, or if the cuts crossed each other at different angles you'll end up with a whole load of loose skin flaps.
I'd put my money on the whole area being a bloody and infected mess in short order....especially on the palm of a five year old. The area is going to be flexed whenever the hand is used, and I've yet to meet a five year old who could keep their hands clean, never mind care for a wound well.
Even if you somehow manage to keep the wound clean, the skin, if it somehow manages to heal is going to become stiff and lose it's flexibility. There's a very good chance that function in the hand is going to be compromised.
You'd have a better chance of being able to pull this off if you move the cuts to a more stable, less mobile piece of skin away from the hand.