I thought the ice situation was a person by person issue. I do have to use it on my neck for tos migraines Cervogenic, and it does not flare my RSD. If I get the heat changes to my RSD foot though, like blow tourch is hitting it, I use Rice and Ice...
fakes out the signals from the foot and I can catch the flare early with this trick.
It is a Blue gel of ice to sit on floor under the foot for ten econds, and then ten seconds of a bowl of rice, then repeat a time or two. I do NOT have a habitual flared RSD foot though.

My PT taught me this trick for my hands and do it for my foot.
di