Hello.
Thank you for your query at DoctorSpring.com.

I understand your anxiety but let me reassure you that the sexual act you have engaged in carries a very low risk of transmitting STDs.
Practically speaking, you have nothing to worry about.

STDs of serious concern like HIV, Hepatitis, Syphilis, Gonorrhea, Chlamydia etc all spread through contact with infected body fluids, mainly through anal/ vaginal penetrative intercourse. I am yet to come across any of these cases acquired through oral intercourse.

Herpes simplex (cold sores) can spread through skin to skin contact but most adults are already infected with it. Even if you are not, chances of transmission are high only in the presence of active lesions. If the lady in question did not have any such skin eruptions, you shouldn't be worrying.

And if you had caught an infection, you would be manifesting symptoms like fever, malaise, rash etc., which I presume you do not have.

In summary, your encounter is very low risk for STDs and does not even require testing. So please do not worry.

I hope this was helpful. Feel free to ask queries.

Regards.