The corresponding tooth can be slightly recontoured and polished. This might give you immediate relief. The white area on your tongue could mostly be due to friction which causes Frictional keratosis. Get it evaluated in a Dental office. Ask one of your family member to evaluate if you grind your teeth while you are sleeping, if you yourself aren’t aware about it. Your Dentist can also evaluate your teeth surfaces and the way you bite and accordingly suggest a Bite guard/ night guard if required.

Get the adjacent tooth in question grinded or eliminate it's sharpness by dentist asap.

Sharpness of tooth is very minor issue & can be easily corrected by any dentist But whitish lesion on the tongue need not be taken for granted. That can get serious.

If it is happening particularly at night time use  night guard (soft) to protect your tongue . If any sharpness on tooth is visible ,or you can feel by tongue please get it removed by nearby dentist ..