I’ll start with the Porsche 997, the 996 looked alright imo, but it looks “like a 90s Porsche”, the 997 made it look sleeker and more modern. Still looks good today.
As for cars that looked worse after a facelift? Maybe the facelifted 6th gen Camaro? The 6th gen looked great pre-facelift, but they did something weird with the headlights and now it looks so-so…
A few off the top of my head:
Tesla S (from 2016 to 2017)
Land Rover Range Rover (from 2009 to 2010)
BMW 7-series (from 2004 to 2005)
BMW 3-series (from 1987 to 1988)
Technically, the L322 Range Rover had two facelifts: one in 2005/6 and one in 2009/10. And really, the 2006 was an odd one-year model with the exterior facelift and new Jaguar engines, but most of the BMW-era interior. So, it was more like 2003-2005 -> 2006 -> 2007-2009 -> 2010-2012 (US model years).