A test at 6 weeks is conclusive so no further testing is needed. Cant say what that sore is, but it is not syphilis.
Oral carries a low risk for syphilis anyway and mutual masturbation (touching around the vagina) is no risk unless you rubbed it into an ulcer.
Couple things to add, the oral sex was received and the encounter was with an escort. The company who ordered the test for me said it was 97-99% accurate at 3-6 weeks. Feeling pretty anxious, what would the chances be?
Would a second test at this point be conclusive (7.5 weeks post exposure)?