If you know it wasn't penetration, you are just wasting your time getting worried about it. As a matter of fact, even for a proper penetration for such a short time, the risk would be miniscule, most people with out OCD won't worry about it.
Bottom line, if you didn't penetrate, you don't need to test, see a therapist for your anxiety. HIV isn't your concern.
The risks for HIV are having unprotected vaginal or anal sex with penetration or injecting IV drug needles. Are you saying you penetrated without condom? Only you would know if you did and if you did, that is a risk. The tip of your penis should always be covered with condom if penetration occurs to prevent HIV. Would this be a big risk? Absolutely not. There is less than 1 percent chance of transmission from a single encounter of vaginal sex. Which means it is highly unlikely. But IF you penetrated without condom, I would take a 4th generation DUO test at 28 days or after to be sure.
The small insert was just on the tip and it was only once I didn’t fully penetrate