Great news for Josh Jacobs and the Raiders ... the massive gash the NFL star suffered on his forehead after crashing his car in Las Vegas last month is healing up well.
The running back showed off his face in videos on his social media page Wednesday ... and you can see, there's hardly any remnants of the huge cut that was so prevalent on his noggin just four weeks ago.
As we previously reported, Jacobs sustained the wound after wrecking his ride at around 4:42 a.