I think the Haitian would have to be around Peter both during the cutting and the healing of the wound. Scar tissue forms during the normal healing process, and the super-healing would never kick-in if the normal healing process has already done its work.
Interesting question, though: would his face heal correctly (back to its pristine state) if he were to cut off the scar tissue, or would the body just assume that that the scar tissue was "normal"? My guess is that the latter is true. Otherwise, Peter's muscles might not heal correctly (given that scar tissue appears necessary for muscle growth). That might imply, though, that the healing factor has a "mental" element which could be manipulated. Perhaps Claire and Peter have the ability to choose how their body heals (stronger muscles, new facial features, etc.).
Interesting question, though: would his face heal correctly (back to its pristine state) if he were to cut off the scar tissue, or would the body just assume that that the scar tissue was "normal"? My guess is that the latter is true. Otherwise, Peter's muscles might not heal correctly (given that scar tissue appears necessary for muscle growth). That might imply, though, that the healing factor has a "mental" element which could be manipulated. Perhaps Claire and Peter have the ability to choose how their body heals (stronger muscles, new facial features, etc.).
