Out of curiosity, what’s the damage like without the Illusion of Pain node on Bone Curse?
Also, the double cast node does cost health to cast, but since you’re low life that’s irrelevant.
Edit: Also also, I wonder if swapping the crit multi roll on your amulet to a phys pen prefix might give you more damage.
Edit #2: From the looks of it, you’re getting +115% crit multi from Marrow Shards & +40% from the Necro tree, plus 339%-387% (I’ll use the average of 363% for simplicity) from your gear per the gear planner for a total of 518%.
If you removed the crit multi prefix from your amulet, you’d have 336% + 155% = 491%, therefore the crit multi prefix on your amulet is giving you 5.5% more damage. Given that the t5 phys pen rolls 8%-9%, that would be an increase to your dps (more so against a mob with phys resist).
If you had min rolls on your gear you’d have 155% + 315% = 470%, a max roll crit multi prefix on your amulet would be +29% which would be a 6.2% increase, as compared to the 8%-9% you’d get from the phys pen (more so against a mob with phys resist).