I'm so sorry that it took them this long to discover that you most likely have RSD! I first started my symptoms in Nov. 2012 - like you, my leg was first and turned red/blue/purple, the pain unbelievable - but it clued my doctor in that something was wrong and so began the rounds of specialists. I believe it may be a ganglion block that you were trying to remember? (Don't worry, brain fog is part of RSD!) I haven't had one but from what I've researched it's a quick procedure - just a few minutes (probably after all the prep part is done). They most likely hope to see if you will feel relief from pain. If you do, they can schedule several to be done until you get the best benefit. My only thought is that you really want a doctor versed in and familiar with treating RSD - not just any doctor however well-meaning they might be. RSD is a difficult disease to treat/manage especially as you have most likely gone undiagnosed for some time. Also, now that you've said hello - try to find the RSD part of the forum for a way better answer than mine! That's what I'm going to look for now too - hope I see you there. PS: It helps to read through the intro items above where you said "hello" to figure out how best the site can help you All the very best!