Can 1 get pregnant from precum on labia majora? Because I know precum has no to low sperm count and vagina's acidic nature kills most sperms entering

Probably not... Your described scenario will most likely follow your wish for not getting pregnancy, but no contraceptive measure provides 100% guaranty. In reality, very occasional accidental pregnancy occurs in the situation you described, just watch cautiously for possible pregnancy, and do home pregnancy test soon after missing the expected period. More detail? Ask Doc timely.