You are right that typically hot flashes are a symptom of menopause, caused by changes in blood flow through the blood vessels in the skin by fluctuating levels of hormones. In your case, since you are only 23 years old, this is unlikely to be what is going on! However, rarely, there are cases of low sex hormone levels in young people; in particular, if you have irregular periods suddenly, then this might be a problem to consider with your doctor
Most of the time, in young people, facial flushing is not a medical problem. Sometimes, in the winter, facial flushing can be worse when moving from a cold to a warm environment. This is just a normal reaction of blood vessels in the skin to the change in temperature. Similarly, facial flushing can sometimes be brought out by stress or by anxiety.
If you have, in addition to facial flushing, other concerning symptoms such as jitteriness, weight loss
, palpitations, and sweating, then the flushing might be a sign of an over active thyroid gland, something that your doctor can diagnose with simple blood tests.
I recommend that you get a physical examination and an opinion on these symptoms from your primary care doctor
at your earliest convenience.