The risks here are really pretty low. You could get anal gonorrhea, chlamydia, genital herpes type 1 (if you don't already have it orally - think cold sores), or syphilis.
If she didn't have any oral sores, I wouldn't worry too much about herpes or syphilis (and syphilis is uncommon in most developed countries), and because gonorrhea and chlamydia reside in the throat, and nothing on your body was actually exposed to the throat, like it would be if she performed oral sex on your penis, the chances are lower.
Most experts don't recommend testing after one incident of oral sex, and this is lower risk than that, so I don't think you need to test.