Hello, I engaged two times into giving oral sex to a guy. I used condoms on both times I gave oral sex. I understand that using condoms reduces the risk for STI. What concerns me more is that my lips could have been into contact with the uncovered part of the skin like the base of the penis and the scrotum.

Performing oral sex on a male is a relatively low risk event and the use of a condom makes it virtually no risk for most STIs (including HIV, gonorrhea and chlamydia).   Furthermore most people do not have STIs.  Theoretically, contact of your lips with parts of the penis or scrotum which were not covered by the condom might have led to acquisition of HSV or syphilis IF an obvious lesion were present.  Without a lesion there was close to no risk.  From what I see there is no medical or scientific reason for testing.  ---

The HPV vaccine is highly effective for prevention of any of the 9 HPV types contained in the vaccine.  By age 45 , presuming that you have had multiple previous sexual partners, it is likely that you have had several HPV infections in the past somewhat reducing the benefit of the vaccine, whether you are aware of it or not and that they have resolved.  For most people HPV is an innocuous infection.  The benefit of the vaccine for you is marginal.  It would certainly do no harm but it's benefits are debatable.   ---