I can't take the heat either, nor the cold. Luckily where I live the summer temperature rarely reaches 30+.Today it's 30+ degrees celcius and i'm totally floored!
I don't know what to suggest but cold showers and keeping your hair wet in between showering to help bring body temperature down. Also take all clothes off except underwear, if you can. I had to do this one unusually hot summer day, the summer before last.