Had unprotected oral sex from a sex worker. i had 4th gen ab ag test done at 8 weeks. std doctor said this is conclusive no more testing needed. is this agreeable?

First, HIV transmission oral to penis is extremely rare, if it occurs at all, so you were not at risk for HIV and didn't need testing at all. However, the AgAb tests are conclusive any time 6 weeks or more after exposure, so your negative result proves you were not infected. No further testing is necessary.

It is overwhelmingly correct. Suggest you avoid such encounters in the future for when having sex of any kind with an unknown person always carries risk. Pl always use discretion and prophylaxis.