A long time ago when I worked on a seismic crew we found ourselves cutting lines through the brush in a river bottom. Millions of ticks would swarm up your pant legs in a red-brown cloud looking for any opening to your skin. It was not unusual to see someone strip down in the field and burn the ticks off of their clothes. I carried a large knife and used the blade to peel them off my pants by the hundreds. It was crazy how thick they were. They seemed to be hanging on every pecan leaf and on the grass under the trees.
We began treating our boots with diesel to try to repel them. That worked to a point. It didn't take long to reveal the shortcoming in that method - diesel fuel soaks through the leather and easily enters the skin. It ruins the boot leather and burns your skin so that wearing anything on your feet is very painful so we abandoned that method.
After looking at options we decided to use cattle ear tags because each cow only uses one and it keeps them tick-free. After reading all the warnings about safe handling - wear gloves, avoid skin contact, potential reproductive harm, cancer risk, etc. - we decided that it made no difference. We realized that this had to be absorbed through the cow's bloodstream from the puncture on the ear and since every cow we had ever seen had an ear tag, this meant that this chemical was present in every steak or burger we had ever eaten so wearing one long enough to complete the part of the survey with the tick problem wasn't going to increase our risk of any adverse effects.
We bought a pack of tags and each hung one on a boot and never had another tick.
I don't have any known health issues to report here 40 years later. Totally anecdotal information from what is likely to have been a low-dose, short duration exposure event.