It is best not to expose the skin. A foot rub is helpful . Work especially on any areas where there is tension or tenderness. The feet are often tense during pain and a foot rub will relax these areas. Make a tea of white willow bark and wild lettuce daily.
White willow is the source for methylsalicylate.
Its effects are cumulative in the system, so keep drinking it on a schedule whether or not you feel pain, and you will get better pain control in persistent pain relief. Then set it off the heat. Then it is ready for use. Make it daily and drink the entire quart over a day's time. The drugstore has a topical ointment called Zostrix made from capsicum, red pepper, or cayenne pepper.