I removed the trip computer to replace the lights and now my fingers are so big that I am having trouble screwing it back in. I managed to get one screw in and I dropped the other one somewhere inside the dashboard and I can't find it

Any idea what size screw I need to buy to replace it? Any "tricks" to getting these back in would be appreciated.

 

You don't need to put the screws back in...I never did. The friction clips work just fine.

If you do feel you "need" to get it back in, I'd go to the hardware store and find a similarly threaded bolt and use that. I think its easier to grip, turn and ultimately fit a socket in there.