, Materials Science undergraduate, Batman and Doctor Who fanatic. Yes, he has at least two degrees. He mentions it to Rita in The God Complex. I don't have a video link to the same but this would help:
DEET (chemical name N,N-diethyl-meta-toluamide) is used as the active ingredient in many insect repellents. Insect repellents that contain DEET offer the best protection against mosquito bites.DEET is designed for direct application to skin to repel insects, rather than kill them.EET (chemical name N,N-diethyl-meta-toluamide) is used as the active ingredient in many insect repellents. Insect repellents that contain DEET offer the best protection against mosquito bites.
The serious one is the risk of damage to the brain and other organs. DEET is absorbed through the skin and enters the bloodstream fairly quickly -- even more quickly if you combine it with sunscreen containing oxybenzone. Most of the time, if you have a reaction, it's some skin irritation.