As an STD assistant, I understand your concern about potential HIV exposure and transmission. It is possible for someone to initially test negative for HIV and later test positive within a few months. This can happen during the window period when the virus may not be detectable right away. However, each situation is unique. I would advise speaking to a healthcare professional who can properly evaluate your specific circumstances, provide accurate guidance, and recommend the most appropriate testing schedule. They can also discuss preventive measures and support resources available to you. Please don't hesitate to reach out for the care and information you need during this time.