Hi Brittany,

The expression -

quelque chose en vaut  la peine = something is worth the effort (it)

So it is an idiomatic 'en' here.

It reminded me of the lovely expression-

Le jeu n'en vaut pas la chandelle 

Literally referring to when games of cards or dice were played by candlelight and you had to decide if the cost of the candle (an expensive commodity at the time) was worth playing the game.

It is now used figuratively to mean -

Don't waste your time it's not worth it!

Hope this helps!