If I take the Knight in h5 in this position, am I getting checkmated?

Hey,

hoping someone can help me out here.

I recently played a game where my opponent playing nh5, which looked suspicious. I played h6, just looking to kick the knight back, however instead of retreating, he played h4?! I've seen a trick in the ruy lopez opening where if black takes the knight, and after pawn takes pawn, white must move his knight. But then white has the powerful Qh5, with the threat of mate on h8. Is there any way to defend this, or is it best to not take the knight?

Here is the position after nh5.