My LED sensitivity also went away recently during the 8 days that I had a recurrent low fever (100-101F) during a very nasty respiratory infection. I don’t know what the virus was - my whole family had it but repeatedly tested negative for Covid and one of us also tested negative for flu and RSV. We heard kids here were showing up at the hospital with similar breathing issues from rhinovirus at the same time, so that’s a possibility.
Before getting sick, I had a little pressure behind my right eye that was residual from too much flicker exposure a few weeks before - a typical long-lasting symptom for me. As the fever started, I felt the flicker head pressure noticeably drain away within several minutes. My head felt unusually clear - all of the flicker-induced brain fog was gone during those 8 days. I was able to use screens without issue throughout the fever for the first time since my flicker sensitivity started in 2018. My inflammatory response was definitely quite active elsewhere in my body during the illness in both expected and unusual ways. I’ve suspected that my flicker head pressure might be due to inflammation, so maybe there was too much else going on during the fever for the inflammatory response to bother with flicker. If the infection hadn’t been unusual and a bit scary, I would have said that my head was better off during a fever than weeks post-flicker exposure. Once the fever broke, the head pressure returned over the next 2 days, with infrequent, strong spikes of pain that were different than anything I’ve experienced before. During those 2 days, I also had trouble getting sufficient blood flow to my brain - I had to lay down with my feet propped up or very actively move my skeletal muscles to promote venous blood return. The rest of my family just had very bad colds without my additional bizarre symptoms- I wonder if/how my over-sensitized system might have played a role in that difference. Luckily I’m back to normal again, but also back to “normal” in terms of being extremely sensitive to flicker.