My iPhone 6plus got overheated in the direct sunlight; will there be any significant damage? It's a brand new phone...

I accidentally left my iPhone 6 Plus about 40 mins outside in the direct sunlight and it overheated. And I got this screen message, "iphone needs to cool down before you can use it". I am afraid I damaged my phone. It is a brand new phone... After cooling down in the shade the screen message disappeared. It seems to be working fine now but my questions is, will there be any significant damage to my new iPhone6 plus? Help!!