you should talk to your dentist about this. i do not know what type of night guard you have but there are appliances that can be designed to protect your tissues from your teeth. in addition the rough edges of the teeth can be smoothed out so that they do not damage your mouth. all of this can and should be evaluated by a dental professional.
how can i prevent my teeth from ripping the tissue under my tongue at night? i have bruxism and wear guards.