Mutual masturbation is an abnormal way to get any STD. The only realistic case would be touching a chancre and getting syphilis. You said you were fingering that lady, and then you touched your penis. If her vaginal fluid got inside your urethra there was a theoretical risk of gonorrhea, chlamydia and herpes, but risks are negligible.
You can test as follows:
-3 weeks after the exposure, for gonorrhea and chlamydia.
-6 weeks after the exposure, for syphilis.
-3 months after the exposure, for herpes.
All the best.
There is no risk from this.
Here are some posts from our experts (when we had them) that may help -
https://
www.medhelp.org/posts/STDs/Nervous-about-mutual-masturbation/show/2183476
https://
www.medhelp.org/posts/STDs/Mutual-Masturbation-STD/show/1968429
https://
www.medhelp.org/posts/STDs/mutual-masturbation-sti/show/1858544
https://
www.medhelp.org/posts/STDs/Understanding-the-risks-of-mutual-fingering/show/1516796
https://
www.medhelp.org/posts/HIV---Prevention/Vaginal-fluid-on-hand-touched-inside-of-condom-and-head-of-penis/show/1119533 - read this thread thoroughly. There is an excellent explanation about why certain activities are not risks, and why others are.
I expect all your tests to be negative based on what you describe. Make sure you are drinking plenty of water, lay off the alcohol and caffeine if you drink a lot of either or both, and if your symptoms linger, follow up with your doctor.