Seems like normal issues

Since it's reducing in size...wait fr 1-2 days ...white lines in jaw can be dur t cheek biting..have u recently got capping done

Mass that u r asking about plz tell me the history of it ,like how much is its size and how and when it arrived ? And white line also

This white line is usually due to cheek biting caused by continuous trauma to the cheek due to slight malalignment of the teeth. It usually does not require any treatment unless it is symptomatic. The only prudent step would be to visit a dentist for a proper clinical evaluation to see if anything can be done to any sharp edges of the teeth so that for the trauma in the future can be avoided. Regards.