For temporary relief get the teeth cusps grinding done.. If the cheek biting recurs after repeatedly grinding of tooth, you would need to get the tooth extracted.

This is very common problem that arises during the eruption of wisdom tooth in the mouth at this age . Kindly visit your nearest dentist asap to get the sharp edge rounded off . And get it extracted in near future as it will give you trouble on and off

Dear practo user This is a very common problem occurring with wisdom teeth. The best way, is to get the sharp cusp rounded off or smoothened by a dentist. But it may not help in the long run. When this problem recurs, it's best suggested to get it removed for permanent relief. Unfortunately there is no home remedy for this, except avoiding chewing on that side, or being very careful while chewing, which is practically impossible. For relief from pain, you can apply mucopain gel over the affected area. But this is only temporary.

Best thing to do is to get the sharp edges of the tooth smoothenend by a dentist.