Look at the surface of the leaves. If your plant is indeed infested with spider mites, the leaves may have yellow blotches on them. When light falls on the leaves, you may see a silvered look or even streaks of bronze or silver.
Healthgrades Editorial Staff. White patches in the mouth are a common symptom of infection, inflammation, trauma, malignancy, and other underlying conditions and diseases. Mouth white patches result from pathogens, such as bacteria, viruses and fungi, which inflame the lining of the mouth causing swelling, redness, and ulcer formation.
Mouth Sores (Definition) A canker sore is a painful, open sore in the mouth. Canker sores are white or yellow and surrounded by a bright red area. They are benign (not cancer). Canker sores can run in families. They may also be linked to problems with the body's immune (defense) system.