The Old Geek is worried about bad flashlight apps which could be malware. Leo says there's nothing to worry about. Both the Android and iOS app stores scan all apps and disable those that have malware. And even better, today's modern OS offers that flashlight capability natively.
There is a bug that could brick an iPhone if you set the date to January 1, 1970. There's a scam going around suggesting if you put that date on your iPhone, it will show a retro Apple logo on the phone. It won't! If you have fallen for this, just let the battery run down until it dies. That will wipe out the RAM and reset the phone to the proper date. But do not restart it!