Basically, everything that could be checked was checked—CT scans, ultrasounds, nucleic acid tests for various viruses—and there were no problems...
Although I still didn't know why I developed a low-grade fever every night, at least the two most suspected and serious illnesses, tuberculosis and lymphoma, could be ruled out.
No bone marrow puncture was done, but the blood counts were all good, so the possibility of leukemia relapse could also be ruled out.
At least there was no immediate danger to my life, and since I had no obvious physical discomfort, no treatment was given.
Going forward, I would most likely adjust my sleep schedule and diet, then continue observing... because there was nothing left to test right now.
Updates should resume tomorrow.