I know that when you repeatedly remove/insert an SD card it can leave "lines" on the gold contacts of the SD card itself but I haven't had any issue with it for over a year (if I'm understanding what you're saying.) Not all SD cards do this and if you're curious check this post out.
As for the camera messing up the card itself, do you have any other SD Card to test it? I'd recommend first getting the card, formatting it on the camera directly and taking a few test shots. Afterwards, power it off and take out out of the camera and plug it in.
Are you sure that:
- The SD card you have isn't in the locked position (SD cards can be "stuck" in the lock position. Tape and cover over the area and you should be good if that is the case.)
- The SD Card reader on the computer is working
- The SD Card is inserted in the correct orientation (shouldn't be a problem but worth checking)
- The SD Card isn't too old/damaged (Old cards I've found tend not to retain data as well as newer cards.)
- The Images you are viewing aren't RAWs? You may need additional software to view Nikon Raws (NEFs or related) See another post
- The image count on the camera is decreasing with each shot.
- The images are directly viewable on the camera when you're previewing/looking at past images.
This isn't an exhaustive list but a good starting point. Should the card itself be the problem, its best to just buy a new card and throw the old one, probably will have more problems in the long run and cards are relatively cheap and getting cheaper nowadays.