。
Excitement and anticipation made her face flush.
Literal
She [topic-は] anticipation [from-で] excited [and-て] face [object-を] caused-to-flush.
顔を紅潮させる is a pleasingly literary phrase. 紅潮 ('reddening, flush') combines 紅 ('crimson') + 潮 ('tide'), giving the image of color rising like a tide on the face. The verb 紅潮する is intransitive ('to flush'); the causative 紅潮させる adds the agent — but Japanese often uses the causative with one's own body parts as a kind of self-causative ('made [my own] face flush'), the way English says 'she set her jaw' or 'cracked her knuckles.' The で on 期待 marks cause, and the te-form 興奮して chains the excitement into the flushing. The whole sentence has a heightened, almost romantic register.