You can't unequivocally determine the extent of the wound judging by the size of the scar. The thead started by "The Bandit" includes a well documented medical angle, inclding links to pictures showing scars the size of a thumb due to an ear piercing.
Be careful with the conclusion that Alston didn't serve with Kerry. That isn't the crux of ANY of the Swiftee's arguments.
You cannot make assumptions on the severity of Alston's wounds from that scar.
It is a keloid scar, which is common among blacks. Keloid scars, unlike other scars continue to grow over time. He may have suffered nothing more than a scalp laceration requiring some stitches. The scar would then have grown over the years to its current size. Keloid scars are also more common when the same area is injured a second time.
I'm not saying that he did or did not serve with Kerry, just that the size of the current scar should not serve as proof that he suffered a severe injury.
The only real proof one way or the other would come from Alston's military records.
with other detailed info about Alston's service, that "Kerry took over command of Alston's boat, PCF-94, after a battle in which the boat's previous lieutenant had been injured. Alston was also wounded in that fight, a clean gunshot through the arm."
The scar on his head might be totally unrealted.
Where and when was that picture in post #31 taken?