WHAT ARE MY LEGAL OPTIONS WHEN MY DENTIST HAS DAMAGED MY TOOTH?

i want to know what legal options i have. approximately 2months ago i went to my dentist for a cleaning. it was really painful when she was working on a particular area. i informed her of it , yet she insisted i just allow her to continue. upon her finishing my mouth was hurting, and i was told don''t worry, just give it a few days. the pain never left,i''m having headaches,and can''t to this day chew on the right side of my mouth. i returned to the dentist, and he stated she had knocked out my filling. he re-did it, and again i was give it about a wk. the pain never got any better. he actually left flesh actually sticking out from between my teeth. i again returned, and he told me it was due to my bite being off. and he grinded down my tooth. it didn''t work. again i made another trip where he once again refilled the tooth. it again didn''t work, and i''m concerned he, or they have damaged the nerve. or basically ruined the tooth. what can i do about this ???????