Screw nut problem: Screen won't turn on, how can I put it back?

While putting the iPhone 4 back together after replacing the front screen assembly, I lost the nut from the logic board for a screw.

Explanation:

[URL iPhone 4 Display Assembly Replacement|iPhone 4 install guide]

See guide above, it's the yellow screw in Step 13, I still have the screw, but the nut that holds it just jumped out of there and got lost, the same nut you can see in Step 8, holding the orange screw. That one seems pretty solid, so can't imagine how it could get out, but it did.

My iPhone now is overheating around that region, near camera, and wouldn't start, except a couple of times, but then I turned it off and disconnected the batter, for the fear of damage.

Any help or ideas appreciated. Thanks

'''I found this question without answer and I have the same problem. I think I can find this part in the trash, but I don't know how to put it back? should I use superglue to fix it again to the logic board or what?

Thanks a lot'''

UPDATE: I have found the nut, and I put it in the same place, but screen wont turn on.. and overheat is still there