Posting in the hopes googlers will see this. Use voltaren emulgel. It’s an anti inflammatory for muscles you apply to the skin which means it easily reaches inflamed capillaries. Apply ASAP after spotting rash and several times over 24 hours and it will mostly be gone! May protect against outbreaks as no new rash occurs whilst applied and back out walking.
If it doesn't clear up, see a Doctor, because the problem also resembles poor circulation to the feet in some instances. Not worth letting it go if it doesn't clear up. May be nothing or could be something serious.