Hi.. Can understand your concern.. As per your complain a white ring on the gum with central red area is most commonly suggestive of an APTHOUS ULCER. Mostly it heals in a week to 10 days time and is self limiting in nature and heals by itself without any medication. If you have soreness or pain you can apply orabase gel as it has numbing agents and it can relieve pain. Taking supplements containing vitamins and minerals especially vitamin B can help recovering any nutrient deficiency.. Drink enough water to maintain god hydration.. Maintain good oral hygiene by brushing twice a day once in morning and once before going to bed at night. Use antimicrobial mouthwash with water in 1:1 ratio after meals. If it does not resolve or reduce after 10 to 12 days or the symptoms aggravate consult a doctor for ruling out other conditions like viral infection (herpes) or sinus formation due to deeply decayed tooth. Wishing you a sooner recovery.. Thanks and regards.. Dr.Honey Nandwani Arora.