Oral sex is considered to be a very low risk for HIV.
This is because the mouth is a very hostile environment and acts as a barrier against HIV infection by denaturing the virus when it leaves the hosts body.
Proteins in saliva also help to break down HIV and this also inhibits the risk of infection.
You would need to have heavy amounts of cum or precum in the mouth and a gaping wound in order for receptive oral sex to be considered even a low risk.
The only way to know for sure is to test first at 4 weeks with a 4th generation DUO test or else at 6 weeks with a 3rd generation test. And then follow this up at 12 weeks for a conclusive result.
However, I fully expect you to come out of this one okay dude.