sorry, doctor, last time i skipped some important info. I was diagnosed with syphilis (RPR showed 1:64) and got three shots of penicillin. After that, i got RPR test thrice, first time (3months after treatment), the result went down from 64 to 32, but the second time (6months after treatment), it kept at 32, doctor didnt know what happened, just asked me to wait for the next test, the third result still (10months after treatment) 32, and doc believed me got infected again. After first test, I met my gf, and had unprotected sex, when the doctor told me i got infected again, i asked my gf to check, VDRL showed negtive. Do i need to get treatment again? why the test result wont go down? Is there any false negative for the VDRL test? Thanks.

I would have expected a 4-fold reduction by 10 months (e.g. down to 16 at least). I think this is unlikely treatment failure, although you don't indicate your HIV status, as HIV positive people are more likely to have treatment failure.