From a student's perspective, I've heard the Lange is better than the baby Miller in that it is more readable and practical, but it's a bit long and in-depth for a one month rotation.
There's a pocket book that a friend recommended, but I don't recall the name. It's about 300 pages with a very colorful cover, mostly purple, if that rings a bell for anyone. It covers the basics of some of the most relevant phyiso, pharm, equipment and procedures. I'll post the name after I get a chance to ask him what it's called. I feel like you could actually read it in the month you have for a rotation.
These are all more focused on anesthesiology generally and I don't know that any of them offer much for Pain Management.
