found a solution for who dont have orignal screen and currently in 11. something that make touch screen not function currently.
turn off ur iphone 6s, and remove the 4 screws plate, unplug the the only vertical attachment which should be use for home button and front camera connection which also the one u didnt replace . after unplug this one, restart your phone. and this time make take while to come up, anyway once its on the touch screen should work fine now. and now its the time to plug the home button and front camera plug back in , and bang its all good !
let me know if it helped.
this is for aftermarket 6s screen replaced and reset for new phone or even updateing new ios. both worked fine for me. hope it save yours as well