iPhone won't turn on after it fell

So my iPhone 7 plus fell to the ground very hard on its face, when I picked it up the screen was intact but it turn gray so I hard turn off the phone using power and volume down keys. after it turned off for 5 min I feel the back of the phone where the A10 ship and it was extremely hot, only after 10-15 min it started to cool down in this time I plugged the phone to charge and to turn it on but I realize that it wont turn on. I thought that the screen was died so I plugged it to the computer to see if the it can recognize the device but same thing happen, nothing!

My question is how can I know for sure what is the problem with my iPhone?

could it be the power management ic?

Thanks for any help,