Hello surya welcome to HCM,
Discolouration of oral mucosa
and burning sensation on having hot and spicy food are initial signs of NECROSIS
that is premature death of cells of living tissue which eventually may progress to cancer. Do not panic these are just the initial symptoms. few tips to avoid future damage :
.Start with a antioxidant course for a month, Lycopene
2000mcg twice daily gives best result in tissue regeneration,
. Topical application of oral steroid ointment ,
.Topical appication of dentogel gives numbing effect,
. you can start with vitamin C
lozenges twice daily, citrus rich fruits like oranges and lemon juice.
.Few changes in lifestyle, avoid smoking , chewing tobacco , alcohol , carbonated drinks, hot foods ,spices and condiments ,excess coffee.
. Maintain good oral hygiene
by brushing,flossing and mouth rinsing.
i hope you work over these, take care