They usually manifest as:
unpleasant redness in the mouth.
an ulcer in the mouth, typically small and white or yellow and oval.
slight burning sensation in the ulcer area.
Some patients may also experience the following symptoms:
Canker sores are not transmissible. Without therapy, they typically heal on their own in 1–3 weeks, but most people feel better within 7–10 days. Healing time for severe canker sores can be up to six weeks. Citrus fruits can help speed up the healing process and provide relief from the discomfort associated with canker sores.