What would happen if someone's internal body temperature increased exponentially?

Further questions to help elaborate on what I'm looking for:
If someone's internal body temperature went up anywhere from 5 to 15 degrees in a matter of less than a minute, what symptoms would they show that something is wrong? At what temperature would the person faint or die?

This is for a creative writing assignment, I don't have enough knowledge in the medical field. Thank you so much!

Your body is designed to function at a certain temperature. This is due to the many of the enzymes within the body being able to catalyze (aid) reactions in the body (metabolism) that keep you alive the best at a set temperature. If your internal body temperature shot up your body would not be able to carry out internal processes necessary for your survival. You would have a fever, you would start to sweat (sweat cools you down), you would feel dehydrated since you lost a lot of water and electrolytes (sweat). I believe that it’s not how much your body temperature goes up but rather how long stays at that rate that is bad. For example, enzymes can function at 50% (not a fact) at higher temperatures but eventually it won’t be able to keep up with your body and it’s demands.
Ruben - Biomedical Sciences Major

Keep your hands washed and trash kept in trash cans.