When the virus is active on the skin - and in the case of HPV that affects the genital area, we are talking about genital skin here, it enters the body through the mucous membranes.
There are other strains of HPV that affect different parts of the body - plantar warts on the feet, for example - that need tiny cuts or breaks in the skin to enter the body.
It can happen within a few minutes if there is friction.
HPV is really, really common. Up to 90% of us will get it at least once in our lifetimes. The vast majority of us will never get cancer from it.
You had a sexual encounter. I'm not sure if it was because it was outside your regular relationship and that's why you're so freaked out, or because it was a sex worker that's causing your anxiety.
Sex workers don't have HPV at higher rates than the general population. Everyone has high rates of HPV.
Condoms offer significant protection for HPV. Your levels of anxiety don't match the risk.