assume you already have PN in the feet? I had terrible cramps just before PN onset. Now no more cramps

Yes. I was diagnosed with Small Fiber Neuropathy last summer. I've had the foot cramping under control for most of the last year, but recently it has returned.

Possible causes (I'm guessing here):
-Diet (I'm eating a little less, skipping lunch)
-Exercise (knees have been bothering me, so no exercise for about a week)
-Summer Heat Increase
-L-Lysine (I've maintained all of my supplements except L-Lysine, but I looked it up and I don't think L-Lysine has much to do with cramping)

Just to follow up on the recent foot cramping:

I'm up to approx. 850 mg of magnesium per day. Things are improving, each night a little better. Less cramping per se, but still a lot of that weird leg muscle flexing (hard to describe).

Of course, now I'm wondering what the safe upper limits for daily magnesium are.

Fyi
 

Zero foot cramping last night.

Possible Reason #1: The high doses of magnesium are finally working.

Possible Reason #2: I went for a 45 min. walk yesterday, first exercise of its kind in a while.