both times results were nagative.so do i need to worry?

Hello and welcome to e health forum.

Using a public toilet or a using a razor in such toilets does not result in HIV infection.

Since the HIV test was done (though it was not needed) , and it is negative, it confirms that you do not have HIV.

You might consult with your doctor or a HIV counselor, who can counsel you and clear any doubts that you may be having.