Girlfriend has HepB

The real reason I'm concerned here because my girlfriend has chronic HepB and she refused to have sex with me until I was vaccinated fully and had my titer checked. We just started having sex even with though we use condoms but here is my story...

I had the 3 dose series of HepB done. But the last dose, the nurse given it to me incorrectly (I didn't know at that time, I found out later). She gave me the shot in the back of my arm (I have tight thin arms so maybe it did or didn't go into a muscle in the back of my arm I dunno). But the first 2 shots the vaccine was given in the deltoid muscle. Anyways almost 3 months later after my last shot I had a titer check done because my doc told me too in case it didn't work. The HBsAB showed >150 so it shows I'm very well immune. But I know all 3 shots needs to be done correctly to have long term protection. Since the 3rd shot wasn't done right, can these immunity decline or what? It's been now 3 1/2 months since I finished the series. I know I can get revaccinated at least 4 weeks later after the first series was done and I know it's not harmful to get extra shots but is it neccessary?

[Hepatitis Researcher]

You have a responsible girlfriend. Your vaccination worked, forget about the third shots  "incorrectness". Take your girlfriend to the Semmering (if you are still a wiener buecher) and enjoy the protection of a polyclonal neutralizing antibody. BTW Even if the levels fall below the offcial limit in the future, you are typically still protected, it is not just the antibody at work, but powerful memory Tcells are also standing by.