Hello. Thanks for writing to us at healthcaremagic A negative Rapid test at 6 weeks is fairly conclusive as most of the individuals who are infected develop detectable antibodies within a month (4 weeks) of infection, however, it is recommended to test again at 12 weeks to cover for the window period of Infection as some individuals may still not have detectable antibodies until about 10-12 weeks. The lymph mode in your arm pit is not necessarily due to HIV; it may very well be due to a local infective etiology (reactive lymph node). I would suggest that you present yourself for examination to your primary physician. Your physician would examine for other possibly enlarged lymph nodes, regional as well as distant. If this is the only one that is enlarged, then most likely it would be due to a local infective etiology (reactive lymph node) and as a treating doctor I would have started you empirically on a course of an oral antibiotic and then follow it up with a repeat examination after 10 days to 2 weeks of completing the antibiotic course to assess whether it has resolved or is still persisting. Mostly a reactive lymph node would resolve within 2-3 weeks of adequately treating the local infective cause. Regards