The activation pattern for erythromelalgia is symptoms are elicited by heat and alleviated by cold. If the erythema (redness) you are experiencing follows that pattern, you may have erythromelalgia. An easy test would be to place your feet in front of a heater to see if symptoms occur. Conversely, you could place you feet on ice packs or submerged in ice water to see if symptoms dissipate.
COVID-19 infection is known to cause neurological complications. COVID-19 could potentially worsen erythromelalgia in individuals already suffering or trigger it in those susceptible. Which is why it’s important to be vaccinated against COVID-19, particularly if you have erythromelalgia.