Without a class mentioned for your toon, I can give only limited advice on raid healing this.
For the Incinerate Flesh, you need to drop the HoT game and spam a reliable and time-friendly big heal to deal with the limited window. A Holy Paladin should work wonders for this as they can do the tank healing and part of the IF debuff as well. But without this, they just need to get it off ASAP.
Tha's to say if you can handle the healing workload. If not, it's okay to let one drop and heal the aftermath but only if you cannot afford to let a raid member die because of lack of DPS or such. Although your mana will take a beating.
But otherwise, the Healers first priority would be the I.Flesh. Even the Tank healers can get onto it as long as the tanks can manage their health with Cooldowns if needed.
Healing is the source of life. Without it, you're left with death.