This is the 5898th most frequent Japanese word.
みせる
"みせる" (miseru) means "to show" or "to display."
In this sentence, "見せた" indicates the act of presenting or displaying something to others.
彼は新しいゲームのスコアを見せた。
He showed his new game score.
Here, "見せて" is used in a polite request for someone to show or display something.
その絵を見せてください。
Please show me that painting.
In this case, "見せている" expresses exhibiting or demonstrating a certain quality or state.