Rimming (oral-anal contact) is low risk for all STDs and probably zero risk for most of them. The main health problems you risked were non-STD gastrointestinal infections -- but if no nausea, vomiting, diarrhea, or fever within a few days, you can safely assume you didn't catch such an infection. As for all other STDs, the risks really are too low to warrant testing; at a personal level, If somehow I were in your situation, I would not be tested for anything and would continue unprotected sex with my wife without worry. However, if negative tests would help reassure you further, you could have a throat swab test for gonorrhea and, after 6 weeks, blood tests for syphilis and HIV. (Note that urine testing for gonorrhea is not adequate to check for oral infection; You'll have to see a doctor's office for proper testing.)

The risks of any other STDs definitely is too low for testing. And I agree your chin rash and sore throat are not due to any STD from this event.

I hope this has helped. Best wishes--   HHH, MD