It isn't a high risk. If she had syphilis or an active herpes sore, you could get that orally.
Syphilis is uncommon, and to get it, your mouth would need to come into direct contact with a syphilis sore. A syphilis sore would appear between 10-90 days, with an average of 3 weeks. You can test at 6 weeks.
Genital herpes - either genital herpes type 1 or genital herpes type 2 - rarely goes from the genitals/anus to the mouth. It's easy for oral hsv1 to go from the mouth to the genitals, but herpes doesn't like to go the other way around.
If she had a herpes sore, it would be easier to transmit. If she didn't, I wouldn't worry about it at all. You'd see a sore between 2-12 days. You can test at 6 weeks with a type specific IgG test. Please note - there are false positives with the hsv2 IgG. I would absolutely recommend against testing in this situation unless you get symptoms. Unraveling a false positive takes a long time and often, several hundred dollars.
There is perhaps a small risk for gonorrhea and chlamydia. Since nothing is actually physically in your throat, rimming is like cunnilingus - there is a risk, but it's small. Most of the time, these do not show symptoms in oral infections. If you got them, they would appear in 3-5 days. You can test with a throat swab at 3-5 days. You'll have to ask for this specifically. A regular throat swab won't test for these.
There is no risk for HIV.
Overall, I don't think this warrants any testing, and I wouldn't worry.