Hi @hoangnam81305,
No, you're okay. The thing is, when you read through most any of the repair instructions here on iFixit, virtually all of them involve applying heat to the phone; heat the back to loosen the adhesive, heat the front to loosen the adhesive, heat the flex cables; basically for anything that's glued down you will probably get told to heat it to get it off.
The applied heat can range from a hair dryer, an iOpener tool, a heating mat and even a heat gun. Given that most of these are capable of putting out much more heat than the laptop charger you're worried about, you're safe in assuming your phone is fine. As hot as you think it is, it really doesn't compare to the other heat sources I've mentioned. If the phone can survive those, a laptop charger isn't going to hurt it.
Hope this puts your mind to ease.