Iphone needs to cool down after apple upgrade?

I have an iPhone 5 that came in contact with water 2 yrs ago. It has been working fine since then until I did the recent Apple upgrade. Now it is telling me that the iPhone needs to cool down before I can use it. Apple is useless. It is obvious that something in their upgrade has rendered my phone useless, but all they tell me basically is sorry. It seems like Apple pulled off a way to force my phone into an early retirement so I can spend another few hundred $$ to buy a new one. Does anyone know if this is fixable or did Apple screw me?

Apple has been known to do dirty business deals, such as purposely making screens flimsy so that they break easily. I have a similar problem after the iOS 8 upgrade on my iPhone 5, like when I'm playing apps my phone will just randomly blank out and return to the home screen. Apple definitely has some bugs that need to get worked out of the system, that is if they haven't put them there on purpose!