If you believe that someone may have shared HIV with you in the last 72 hours, you can use PEP, an HIV prevention medication, to reduce the chance that the HIV will spread throughout your body. You should see your doctor, an HIV services organization, or an emergency department to get PEP. They will ask you about the situation, make sure you are HIV-negative at the time of ingestion, and monitor you for side effects. If all goes well, they will prescribe you a one-month course of medication that should help reduce your risk of getting HIV. If you find yourself in this situation, you should consider using PrEP to prevent HIV transmission in the future.