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Your salivary gland enlargement is actually due to bacterial or a viral infection, which can be confirmed by a few blood tests and a physical examination by your doctor.
HIV ELISA Tests , check for antibodies against both HIV 1 and HIV 2, and such accredited tests, have a high sensitivity above 99.9%. Hence there should be no doubt about HIV not being detected in your case especially after 6 months. Since your tests at 23 weeks is negative, it is conclusive that you are HIV negative. There is no need to do any further testing with regard to HIV.
You should consult with your doctor who can prescribe you a course of antibiotics, which will help in resolution of the symptoms.