Did you only have the one experience of slight burning? If so, you don't need to be retested.
If it lingers, then test again, but just once could be from dehydration, irritation from spicy foods, alcohol, caffeine, etc.
Hi < i would say no need to retest as the changes of getting gono or chalmydia from oral sex is extremely low risk. amd 5 days would be considered in the window period. You might be causing it your self from constant checking and milking it.
dave