Honestly, I dunno if I'm gonna headcanon Nasir as still having the mark but, as in my headcanon it had been spreading all over his body and causing him agonizing pain (which in the base game every time he/she used it the Inq. experienced a feeling like 'my nerves are on fire'), and still suffering from said pain and everything...
or if I'm going to have him def. be armless as a result of Solas taking it back, and eventually he gets a metal prosthetic arm to replace it. So he'd be the Fullmetal Dwarf. Also give him a Lee Everett moment at some point.
Either way I want Nasir to still be handicapped.
....maybe I could have Nasir have residual energy left inside of him from the Anchor that allows him to tap into the powers he gained from it, sort of. At the very least, Aegis of the Rift.
I dunno it involves a lot of my thoughts on the Anchor as we understand it so meh...
Either way Nasir's still a badass.
I can still bite your legs off.
The Inquisitor's gonna be the new Black Knight.