Temporairy vertical lines on 5S's screen

Yesterday evening, I put my phone in the charger (the official 1A one with the apple logo on the bottom that was included when I bought my phone) and put the iPhone with the display downwards on the bedroom floor (I have a case, so the screen isn't making contact with the floor). I woke up today and discovered that it had faint, thick, vertical lines across the screen that were visible when something darker was displayed on the screen, for example, the notifications centre when it's empty. They slowly faded away and after about half an hour of use, they were gone, or at least not visible anymore. While I waited for the lines to go away, I googled it and it seemed to have something to do with the display connector or the digitizer not working.

Another piece of information that might be important to give you is that we were three people sleeping in this bedroom and that the balcony door was open.

Anyway, I just wanted to know if what I experienced with my iPhone this morning is a common thing that happens when you expose your iPhone to air moisture for a few hours or if it's an early sign that my iPhone LCD and/or digitizer is going to break soon.

Thanks for reading through this and have a fantastic day!