As someone who has gotten her hair colored quite a few times, there is no good reason they should be hot. In fact mine were cold and that helped them to have a stronger color. Definitely should sue for bodily harm. Or if not, see the company and make them give your family and you unlimited free haircuts and stuff.

I hope you went back and told the company!

lawsuit

When you get your hair dyed, the chemicals they usual use generally will burn you a bit, that's normal.

I color almost everyday and Foils do not get hot like that.... Even under a dryer they warm up, but do not get that hot. And correctly placed foils do not touch the scalp, that's the whole purpose of them. It is possibly that you got burned from the bleach- which would mean a) it was way to strong and b) you had a terrible stylist because bleach or color in a foil, is not supposed to touch your scalp. It would mean they used entirely too much, made it entirely too strong, and placed it incorrectly in your hair and it bled out of the foil- which means you also have very ugly spots of colored hair right next to your scalp that don't blend in with the rest of your color. You also would have breakage in your hair from this- you should get a refund based on these things alone. Also, you would have felt a bubbling, itching and stinging feeling before burning. You should have said something at that point. Definitely go back and show them, get your refund and never use that salon again.