My iPhone is bend a little due?

And you can see inside the lights and stuff. Is there a chance this could give me health problems? I mean like nasty chemicals in the components of the phone like mercury? The gap in the side is about 1mm.

No, you will be fine. The Phone however may get dusty or wet in the inside causing even bigger problems.

No it won't affect your health, but i suggest you take it to a service centre because that isn't good for your phone.