Let me begin by saying that this is a rewrite of an already fun and engaging fic. I am only comfortable writing this review so early in the story because I enjoyed the previous one so much and can already tell that this one is an improvement.
There are very, very few spelling/grammar issues. The pacing is slightly on the slower side, but by no means does is drag. The rewrite is still in its infancy so the worldbuilding is still being established, but from what I can recall of the original story it's going to be well-built and internally consistent.
Most importantly, the main character is likeable and competent. He's a former surgen dropped into a medieval fantasy world with no money and no connections. His knowledge and skills are believable and enjoyable to read and don't bog the story down like most insert characters. He attended medical school and practiced medicine for years, so he's very knowledgeable about the human body and how to treat various aliments, but he has no tools and no medicine to prescribe. He doesn't instantly become a respected doctor. If he's going to do anything with his knowledge, he's going to have to work hard and find a clever way to move up in the world. It's executed phenomenally and I highly recomendable you give it a shot.