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There is a definite risk of contracting herpes as well as other STD on having fellatio.
The risk would be higher if you had any open wound or raw area on the penis.
But the risk of getting herpes this way is less compared to giving oral sex to a female.You cannot get tested for STD tomorrow as antibodies to any such infection would not have developed till now and different infections have diffent window period of testing.
By window period we mean the period where one is infected but the tests may not yet be positive as body takes time to develop antibodies which are tested for during tests for STD
You may kiss your child or wife as your genital area would get infected if at all and not the lips
You should avoid having sex with your wife until you are cleared from STD point of view
Different STD have a different window periods
I will mention the window periods for you
For herpes it is 4 weeks to 100 days
So earliest it can be detected is 4 weeks unless the blisters appear before that.In that case smear from blisters is tested
The probability of getting herpes is less than 5 % in fellatio
Chlamydia 2-3 weeks
Gonorrhea 2-3 weeks
Syphilis 3 months
Most likely you will not be infected but you need to get tested
HPV 3 months
Yes you will need to test for all within each one's window period
If you had a sore on penis the probability would be higher than 1 %
A raw area
where the skin has broken down
Yes it should be below 5 %
It has been a pleasure assisting you