Hi Megs,
I get significant relief using magnesium chloride, massaging it into my legs/feet. I believe my current relief is from continuing to use this. Over time, this has helped a great deal. I am very sensitive to meds and often cannot stick with meds. I am now taking additional meds, yet I feel the use of magnesium has been extremely helpful. It is the only way I have been able to get any sleep, via relief of pain and spasms.
The pure magnesium chloride "oil" will sting open cuts/wounds/lesions.
The magnesium sulfate lotion (Epsom) did not sting open skin, in my experience.
I do not know if the other magnesium chloride products (lotions, etc., as shown in the Life-Flo link, will sting open skin or not). I may try the chloride lotion soon.
I have had relief with other topicals in the past, including ketoprofen, bupivacaine. I have not tried ketamine. I have also had some negative reactions to some topicals, yet these reactions, for me, were systemic.
Some of our friends here us topicals I have not yet tried or cannot tolerate.
I do not have good luck with capsaicin. It seems to aggravate matters for me. I had tried capsaicin alone and then by first applying lidocaine and then capsaicin. Yet, still, even 2 weeks later, no significant relief. I am a bit suspicious of capsaicin use in these types of conditions, based upon my own experience. Some people find it helpful with peripheral neuropathies. I have tried it, many times, and it seems to aggravate my condition more than helping.
Please be aware: If a med or substance bothers you, as in an allergy or significant side-effects, when taken orally -- it is very likely to give you the same reaction when used topically.
A literature search will basically show there is no proven efficacy for topicals when used with CRPS . I think the studies have not yet been done. I also feel the responses may be individualized. Some people can use topicals I cannot tolerate, for example. It's truly a matter of simply trying options and finding what works best for each of us.
I hope this helps.

DejaVu