My friend says an area on her foot has a sharp pain, almost burns but refuses to see a doctor. should i be worried and what can i do?

If and when it becomes uncomfortable enough, she will see a doctor. There is no benefit to your worrying. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV, Flu and Covid vaccines. Wish you good health!