If Peter Petrelli can heal like Claire, why does he have a scar on his face?

Question

In Heroes...

Peter Petrelli adopts powers of those he comes in contact with. Eventually we learn he keeps those powers even when not in proximity to the person he's absorbing from. He encounters Claire pretty early on and gets her ability to heal.

In the episode 5 years gone we see future Hiro and future Peter join up and Peter has this slash across his face. We see this slash in other episodes, like in Season 3 when he is caught looking for a gun after his brother is shot.

So much as I can tell, the slash is only there so the viewer can distinguish present day Peter from Future Peter and I don't recall any point where he took damage that sliced his face and didn't heal.

Anyone know how this scar got there and why it doesn't heal?

Answer 1

As stated on heroeswiki.com there are several references to at least two scar varieties on Peter Petrelli's face.

Alas we'll never know what caused it and why he did not heal it:

Writers Joe Pokaski and Aron Coleite said about Peter's scar, "First, it is not a mistake, Peter can regenerate, but he still has the scar. Secondly, we'll show you how later on in the series. We promise".

Heroes being cancelled this promise now is void.

References:
http://heroeswiki.com/Peter%27s_scar
https://www.cbr.com/behind-the-eclipse-heroes-week-21/ (origin of the writer's quote)

Answer 2

It's a cautionary reminder

Future Peter's facial scar runs from the right side of his forehead to his left cheek:

— Image source: heroeswiki.com

In "I Am Become Death", Future Gabriel (a repentant Sylar) cautions Present-day Peter against following the Sylar path. Gabriel explains that he keeps his broken Sylar watch as a scar to remind himself of his past misdeeds. The watch has a cracked face, with the crack positioned similarly to Future Peter's scar:

— Image source: www.writeups.org

Gabriel's son Noah is happy to see present-day Peter and is surprised that Peter doesn't have his scar. Since the Peter of this future timeline has earned the trust of Gabriel and his family, Peter and Gabriel likely have similar opinions about the potential dangers of their abilities.

If Future Peter has any conscious or subconscious control over his healing ability, he may have chosen to keep his scar for the same reason that Gabriel keeps his broken watch.