@idonotlikeusernames has it right. A Theurge who understands well enough how the skin heals itself could undo a scar by temporarily enhancing the healing telos of the skin. A less proficient one could heal wounds but leave a scar. A clumsy one who just wanted to increase the smoothness of the skin (something much easier to comprehend than the telos of healing) could temporarily remove a scar, but it would come back as soon as the blood ran out.
