If your repair shop was certified by your insurance company, they should be required to offer warranties on their work. Even if it is an aftermarket hood, it should still meet the requirements of the vehicle. It's possible the repair shop might have forgotten to install an insulating heat shield, or it just might be normal with that replacement body part.
It's perfectly okay to return to your repair shop and ask them if it is normal for the hood to be hot to the touch after running the engine for a period of time. The weather has also been unusually hot lately, and it's possible that the hood is hot simply because of exposure to the sun combined with the engine's heat.
I've also forwarded your question to our experts who know more about body repairs, and hopefully you will hear from one of them as well.
For additional assistance, please find an AskPatty Certified Repair Shop at http://www.askpatty.com/search/?type=all&m=30&q=&keyword= and they can help you diagnose and repair the problem.