I use ThermaCare patches on my arm when the weather is cold, and it helps warm my whole arm and body and keep flare-ups in check. I wrap one of the arm/neck patches just below my elbow, and it works for about 8 hours. There are different ones for arm or neck, back, or menstrual pain. I think the arm/neck one might fit well on your upper foot or above the ankle. They are sold (RED boxes) at pharmacies, Walmart, etc., and cost around $2-3/patch. They work like the little hand warmers - they warm up when exposed to air. They stick well. Don't get a different brand - they don't stick as well. I haven't had any problems with rashes from the adhesive on ThermaCare patches.