I typically drew it as "you'd not easily tell" but I suspect there would have been potential scarring. It'd have absolutely attempted to keep its fur groomed as best as it could to hide it unless you were close. Honestly if you were that close the potential scarring Simon had would probably be secondary to "wow, you surgically have nothing there, huh?"

Post-turning is very much a "AHAHA I DON'T HAVE TO DEAL WITH THAT ANY MORE" situation in that Simon probably goes for what it ideally wanted.