It might be... sodium is part of sodium bicarb. Sodium channels are in the pain receptors too. Sodium bicarb is also basic, and the skin is mostly acidic. The drugs used to treat PN are often sodium channel blockers... like the lidocaine.
Here is a typical bicarb soak instruction:
http://www.armhammer.com/mybody/body_tips.asp
Plain epsom salts has no sodium. Only magnesium and sulfate.
It might also burn if too much is used at a time, and with too hot of water.
I have never had a epsom salt bath burn or sting however. That is the only thing I will soak in.
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Weezie looking at petunias 8.25.2017
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