My primary medical contact throughout all this, Linda, has confirmed my fears that the magnet seems to be extruding/rejecting. From Linda:

Looks like your body is working super-efficiently and I might not be surprised if it popped out in the next few days, like in the night when you’re sleeping. This pic looks very much like a bullet I saw buried near the skin (it had migrated down his arm) that extruded the day after I saw it.   So hurry and get to Denmark now :)  !   next transhuman adventure… ?

I remain hopeful but not optimistic about the permanence of this magnet – the sharp edge is getting more and more pronounced on my skin… Unfortunately, due the the necessity of the insertion method, there’s a nice edge of the disk that gives a great ‘blade’ for my body to push against the skin with :( On the Biohack.me forums, there’s an imminent release of a new magnet with a coating that’s more resistant to fouling that I’m excited about. I’ve also sourced ULTRA cheap lidocaine and suture kits, which were my two biggest expenses – given my current supplies, I can get enough lido/needles for 50 more implantations for $25, and stitch kits for $3 each.

Beyond that, I’m waiting on information about the new magnet/form factor, possible alternate locations, and most importantly, research on how to prevent extrusion – I want to learn more about incision angles and depths of other implantees, and how they ensured healing didn’t result in rejection. I’m disappointed that my magnet may not be much longer for my body, but more research is giving me a nice hobby to pick up again to distract me from long days at work. I’m also excited to get more surgical experience in general. Plus, I owe my possible future audiences in Denmark a EM sensitive finger! ;D