The back end of the camshaft position sensor broke off

If you are not able to get them out with needle nose pliers then you are going to have to remove the valve cover and retrieve them. There is a chance that they will settle into a place in the top of the head that does not cause an issue but I would not leave them as the result could be damage to the engine.

Let me know if you have questions. I attached the process below for the right cover. Thanks