Products that contain DEET are tick repellents. Products like Permanone contain premethrin and are known to kill ticks. However, they are not to be sprayed on the skin. Permanone can be sprayed on clothing. Once it is dry it is assumed to be safe.
Ticks are anti-gravitational.
They are generally seeking the highest point. If they get on your body below the clothes line, one hopes they will travel up and die once they come in contact with treated clothing. Lyme Disease is a 12 month problem. The best defense against LD is education. Know your facts.