Anytime a penis enters a vagina or anus there is a degree of risk, but the amount of time exposed to fluids does increase the risk. Because your penis never entered her vagina, there was no risk. “Tapping” your penis against her vagina for a few seconds does not constitute any risk at all. Also, this is a second question ive seen where a man claims a woman “forced” him into having sex or do something without a condom. You say your event was with a CSW which is a sex worker that you obviously paid to perform sexual acts with you. And you tapping your penis on her vagina was a decision you obviously had to agree with so please dont make it sound like she sexually assaulted you to make yourself feel less guilty.
That is not close to penetration. You are safe and can move on from worrying.
This answers all of your HIV questions, and if you can think of any more just reread about the 3. You had zero risk therefore testing is irrelevant to your situation because you had zero risk. HIV is a fragile virus, which is instantly inactivated in air and also in saliva which means it is effectively dead so it can't infect from touching, external rubbing or oral activities. It doesn't matter if you and they were actively bleeding or had cuts at the time either because the HIV is effectively dead.
Only 3 adult risks are the following:
1. unprotected penetrating vaginal with a penis
2. unprotected penetrating anal sex with a penis
3. sharing needles that you inject with.
The only way to get HIV is if you did one of the 3. The situation you describe is a long way from any of these 3.
Even with blood, lactation, cuts, rashes, burns, etc the air or the saliva does not allow inactivated virus to infect from touching, external rubbing or oral activities. This HIV science is 40 years old and very well established, so no detail that you can add to your encounter will change it from zero risk. Because of all the research statistics, doctors have calculated the risk from what you describe to be less than that of being hit by a meteor, therefore no one will get HIV from what you did in the next 40 years of your life either.
If you didn't have one of the 3 then you are just worrying about your own hiv theory - which is unrealistic for you to think that can become reality - so you should move on back to your happy life instead.