How much does it cost to replace a 13 in 2017 Macbook Pro display?

Hi, I was wondering if anyone has had their display replaced and knows how much the process would cost either with Apple or a third party. I have a line of bright and dark spots going through the bottom of the screen. In addition to this, I compared the laptop screen to my sister's 13 inch 2017 Macbook Pro and noticed that mines is a lot dimmer in comparison to hers despite being the same model.