I have been having a pain at the posterior end of my tongue- the part which cannot be seen when you observe yourself. I have no problem swallowing and the pain is restricted only at the posterior end of my tongue and  other parts of my tongue are painless. I also have a painless patch of raised white papillea in the middle of my tongue for the past two days ( new observation) while the pain at the posterior end has reduced substantial after gurgling with glycoseptol but has not completely gone yet. Should I worry? What can be the cause? How long does it take to heal ? When should I consult a doctor?