彼女は緊張すると顔面潮紅を起こす。
She experiences facial flushing when she gets nervous.
ホットフラッシュ is a more common loanword for hot flash, while 顔面潮紅 is a formal medical term specifically referring to facial flushing.
Compound of 顔面 (face) and 潮紅 (flushing, redness). The exact historical derivation is uncertain; the term is used in modern medical contexts.