Dentist perforated my sinus and ruptured a cyst/abscess bringing the bacteria into my sinus what can I do?

A dentist prepped for a crown, and in doing so perforated my sinus. I didn't know what happened until I went home and leaned forward & tons of clear medical smelling liquid poured out of my right nostril. After a week, my face swelled and I got this giant pus pocket in my gums above the tooth behind the one she prepped. During the procedure she told me when I asked if her back hurt, that she had great pain killers. I went back to her complaining my gums were sore and showed her the thing. She kept saying "I didn't go that high" and told me to see my GP for a sinus infection. I ended up in the hospital, ran a CT scan, found out I had an abscess with a cyst she punctured bringing bacteria it into my sinus. Not enough room to write everything but I'm still in pain $12K later. What can I do?