I couldn't just fix the polyflow around the shoulders like I was intending. I ended up redoing the entire torso and the hips, butt and connecting part of the thighs.
I don't know how well it will animate in general but it will be a lot better than how it was. This meant the uv maps had to get redone as well. Then I spent two days trying to figure out how to fix the mess before remembering that 3dC is supposed to be able to deal with stuff like this and looking up how to do that instead.