Symptoms of sexually transmitted infections (STIs) can appear a few days to several weeks or even months after contact. The time it takes for symptoms to show depends on the specific STI and its incubation period. It is important to get tested if you have any doubts or concerns. You can find a testing center near you based on your postal code. It's always better to be cautious when it comes to STIs, as some infected individuals may not show any symptoms.