How bad is it to go on a car ride with other people

I have done two rounds of permethrin 10 days apart. There were some new burrows in between the two rounds, I’ve just finished the second round. My friends were gonna give me a lift in their car back to the UK from Europe (a few days drive) but after discussing it we aren’t so sure if it’s a good idea because I’m not sure it worked.

How risky is it to be sat with them in the car all those times(won’t share a bed)