Read back using the Read function and either do a compare (you are using Tunerpro?) to the original, or just look at the changed map(s).

If you just flashed without looking at what changes you were making, that's not a good idea at all.  This would be a good time to download Tunerpro and start learning...

Just to be clear, you used Nefmoto software and not boot mode?  If Nefmoto, there's a Read button right next to the Write button.  Read your bin back and store it on your computer.  Nefmoto will ask you for a file save location.  Compare this .bin to either the one you thought you wrote, in which case they should be the same, or your original, in which case it should be different.  In Tunerpro, there is a .bin compare function (double click on the identified difference and the map will open), or you can open separate instances of Tunerpro (Tools>Custom).

Tunerpro is an off-line tool.  You will need both .bins available to look at from your computer.

Really, though, if you wrote a file with the correct name to the ECU and the upload process completed, there is no real reason to suspect that it is actually the original.  Unless, of course, you accidentally overwrote the modified file with the original.

Try and get set up with ME7logger http://nefariousmotorsports.com/forum/index.php?topic=837.0  Much better than VagCom, and if you want help from any of the experts on here they will pretty much insist on the increased sample rate.  There's a GUI for it that makes it much safer for using on the road http://nefariousmotorsports.com/forum/index.php?topic=1079.0  ECuxPlot (google search) will allow you to easily graph (it does work for VagCom as well from what I hear).