I had to use my old iPhone 6 as a backup recently when water got into my 6S and the touch screen became erratic and had dead spots on it. Took a few days for it

I had to use my old iPhone 6 as a backup recently when water got into my 6S and the touch screen became erratic and had dead spots on it. Took a few days for it to get repaired (sister-in-law's husband did it for free so I wasn't going to complain about how long it took) so I had to use the old one during that time.