I was looking around for it but couldn't find whether or not you got glans enhancement -- I did read the urethral bleeding and subsequent antibiotics, which tells me your Doctor(s) believe an infection is at play, and a serious one given the potential
Necrosis.
To the extent that it is causing potential
Necrosis is remarkable to say the least; while infections can & do happen (albeit uncommon), ones of this severity involving the glans despite strictly shaft injections is extremely unusual. I'll be frank, I'm not sure I think urethral bleeding should be an acceptable post-op experience from
Dermal Filler injections (and I'm going to have that discussion in the near future), and to what extent urethral compression plays a role in this matter is hard to say -- I'm not suggesting it played a role in the infection, and all things considered it could be and likely is a stroke of misfortune.
Proper filler placement should (in theory) have no meaningful impact on the circulation of blood throughout your penis, and it's really hard to speculate when an infection is involved because all medical procedures that break skin are susceptible to infection, even something as simple as a Dental visit. This is why Clinics practice sterilization of their instruments and environment -- they know the risks remain ever present, but keeping them below a certain threshold is paramount.
The plan now is to manage symptoms and hope the debridement is kept at a minimum -- this involves the full course of antibiotics, and communicating with your healthcare provider any changes in symptoms even while on antibiotics. Our bodies have a remarkable proclivity for healing, and despite your diagnosis & prognosis, I believe you can come out on top as best as can be expected with the ongoing situation. We're here, keep us posted.