It looked bad, and according to Dave Meltzer on Wrestling Observer Radio (subscription required but recommended), that's because it was.
Neville has reportedly joined WWE's extensive injured list. Meltzer says that he broke both his ankle and tibia (shin) on the slide-gone-wrong (which you can see if the match footage above at approximately the :10 mark) that occurred while working with Chris Jericho on the Mar. 14 Raw.
Amazingly, the Brit executes several moves after the injury occurs - including a kick with his bad leg - but all three performers called an audible to end the match with Neville in obvious pain.
Provided the injury diagnosis Meltzer's reporting is final, recovery time is typically in the four-to-six month time frame. Depending on the severity of the breaks, and if there's ligament damage in addition to the bone fractures, it could be longer.
There's never a good time for something like this, of course, but it seems especially unfortunate as the Slammy Award winning, longest-reigning NXT champ in history was in the midst of a run of great matches and increased television time over the last several weeks.
We'll update you with any official announcement from WWE as soon as we get it.