Help - New player Pathfinder Caustic/Scourge build

I truly need help, wondering if I got it all wrong, and if so what can I do for the next couple of purchases to make this build better.. damage is lacking, survivability ok. Flasks up near 100%, 100% avoid Freeze, shock, chill, ignite.

but damage on level 80 rare's is even a long fight. I see people clear 80% faster, could people take a look and offer a little advice on direction with this character.

https://pobb.in/t-yzecjvE-6d

Thanks