I hit s1 on my final game of the episode. i never played a game in this rank, and it doesnt show as my peak?

title says.

I hit silver 1 in my final game and my peak still says b3. is it because i never played a game as that rank? how to fix?

Correct, you needed to play one match after hitting silver 1. This is a limitation of Riot’s public API, unfortunately there’s no fix.