Almost all men have enough testosterone to prevent flushing, and it would be very rare for the steady age related drop in testosterone to cause hot flushes.
In addition, a spot testosterone level alone is not going to be revealing, and the hormonal work up is far more complicated.
The exception is androgen deprivation therapy for prostate cancer, or other meds that lower testosterone, which can act suddenly. Let me know what you are on. If you are being treated for prostate cancer, and have adjusted your meds, this still does not rule out all possible problems.
What is more concerning here is the sudden increase in flushing at age 85.
This can be for a variety of reasons.
Hidden chronic infection.
Kidney disease/liver disease
This is not something to sit around and put up with.
Rather, you need to see your internal medicine doctor [I am a board certified internist by the way...see my profile] as soon as possible.
I am doctor thomas. I am here daily. Find me in medical by request for fast, correct, safe and comprehensive answers.
Please click a positive rating on this answer page [how we are paid].
Come back as needed.