My betta is sick, but what is it?

For the past week my betta has not been eating at all and today she is floating on the top upside down I thought she was dead but she's not. She also has a white puffy thing directly above her eye I change her water when it gets dirty and feed her everyday. So far I changed her water and cleaned the rocks and gravel really well she is not upside down anymore but still won't eat and the patch is still there. Does anyone know what it could be and what to do and how long I have? Please help me.