How do I check if raycast is hitting a gameobject?

Hey I have a problem I need to show some text whenever a raycast hits a building. That's no problem, but if I etc. look up in the sky after looking at a building the text will still be visible. Here's the code:

 void Update () {
     Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
     RaycastHit hit;
     if (Physics.Raycast(ray, out hit, 25)) {
         if(hit.collider.gameObject.layer == 8 && hit.collider != null) {
             actionMenu = true;
             return;
         }
         actionMenu = false;
     }
 }

So my question is... How do I check if my raycast is still hitting a gameobject and if not it should return false.