I left my iphone on the heater all night.

I fell asleep and my phone fell on the heater of my room overnight. Its the winter in canada and i have the heater set pretty high because the cold infiltrates fairly easily during the winter. It was burning to the touch and dead when i picked it up, but 10 minutes after letting it cool down on room temp i was able to open it back up and it is fully functional. Should i be worried for long term damage?