Hi, and thank you for your question
The chance of getting HIV from oral sex is extremely low as indicated in our Know Your Chances charts and on our HIV and AIDS information page. If you are sexually active, we recommend getting tested routinely (every 6-12 months) for all sexually transmitted infections (STIs) including HIV, syphilis, chlamydia and gonorrhea. The best time to test for HIV is 6-12 weeks after an encounter as it can take up to this amount of time for antibodies to be detectable if a person has acquired the virus.
I would add that simply because someone does sex work, this does not mean that they have HIV. In fact you have indicated that this person told you that they do not have HIV and that they are “well-reviewed” on their profile. Whether you engage in sexual contact with someone who does sex work, or with someone you met online or at any other venue, it is important to consider precautions you may want to take against infections. As already noted, oral sex is generally pretty low risk for HIV but other infections such as HSV, syphilis, chlamydia and gonorrhea can be more easily passed this way. Regardless of the partner, condoms are a good way to prevent or to decrease the chance of passing these infections.
Let us know if this does not answer your question or if you have any more questions or concerns.