Just chiming in with a bit of meta for you all. @lucasnator2 made a really good point when reblogging my recent parallels post about the possibility that Roy and Ed could have a scar in very similar locations. Roy seared his wound closed, so there’s no question that he has a scar from it. Ed, however, “heals” his wound with medical alchemy. Like @lucasnator2 said, we don’t know a ton about medical alchemy, but we do know that it can treat injuries as well as diseases. However, I have doubts that using it on an injury would eliminate the possibility of scarring.
In episode 41 when Ed is injured in his fight against Kimblee, he specifically states that he managed to “stop the bleeding.” That doesn’t mean he’s healed. He also requires further medical attention. That leads me to believe that his grasp of medical alchemy (which is quite basic) would’ve have allowed him to flawlessly heal such a serious wound.
But we have another example.
When Riza’s throat is slit in episode 58, Mei is able to save her life with the Xingese equivalent of medical alchemy. However, she also states that she “stopped the bleeding” and that Riza will “still need to see a doctor.” No argument, Mei has a much deeper knowledge of medical alchemy than Ed. If she is unable to completely heal a much less serious (It’s hard to compare getting a gigantic metal rod shoved through your guts to anything.) wound, that leads me to have serious doubts on medical alchemy’s ability to flawlessly heal the human body without leaving some sort of trace.
In both of these cases, all medical alchemy seems to do is “stop the bleeding.” Granted, neither person who performed the transmutations were doctors.
Also, when Riza is shown recovering in the hospital room, she has a bandage around her neck.
You don’t put a bandage on a wound that doesn’t exist.
The official website for the live-action film of Hiromu Arakawa's Fullmetal Alchemist manga revealed the film’s December 1 opening date on Thursday. In addition, the site revealed a new still featuring Alphonse Elric in full CG. The Comic Natalie website reports that the CG Alphonse employs some techniques for the first time in the Japanese film industry.