Karolis, There is a pretty good chance that it is the LCD. What you can try is opening the phone and check/ reseat all the connections and check the board for loose/damaged/burnt components/cracked solder joints and reassemble and try. If all looked good and still no display probable screen assy. replacement required. Below are links to a guide screen replacement and a link to replacement screen possibly(choose your model at the page), you can also do a search for a screen your self for better pricing perhaps. Good luck. I hope this helped you out, if so let me know by pressing the helpful button.
[guide|77136]
https://www.ifixit.com/Store/Parts/Samsung-Galaxy-S7