What happened to Moses' face after he spoke with God?

Answer: It was radiant

Coming down from Sinai with the tablets, Moses did not know his face was radiant (KJV: shone) from speaking with the LORD.

“And when Moses came down from Mount Sinai with the two tablets of the Testimony in his hands, he was unaware that his face had become radiant from speaking with the LORD.”— Exodus 34:29 (BSB)