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The foul smell and discharge both suggest infection. Visit a gynecologist (not regular doctor/GP) for a complete evaluation and get the discharge tested along with vaginal smear test and culture sensitivity test. These will help in identifying the exact causative organism along with the best suited antibiotic to be used for complete recovery. Avoid having intercourse (if you are sexually active) while being on treatment and get your partner also treated simultaneously to avoid chances of re-infection.
Maintain good hygiene. Keep the area dry, avoid using tight undergarments, and avoid douching. Use only cotton fabrics for undergarments.
Take care.