Though some help with respect to healing is acceptable to ask for, you should have tried the fight multiple times before coming here. We're not about to explain the mechanics of Wrack to you, you should watch some videos/read up on the abilities and then feel free to come back with healing/druid role specific questions.
This may not be the place to ask, but does Wrack continue going out past p1?
Also, is there a reason why it can't be mass dispel'd immediately by a priest?
One last thing...for anyone who's pulled this boss in 10m, would Pally/Druid work as a healer composition for this fight? It's very difficult to find much discussion of this boss anywhere... ):