Old wounds never heal, especially if they're caught on video.
The New York Daily News's Rush & Molloy got their hands on an advance copy of rock-journalist Everett True's Nirvana: The Biography (released in the UK as Nirvana: The True Story) which includes a harrowing scene of Kurt Cobain ending a fight with Courtney Love by stubbing out a cigarette in his own forehead. (Shades of James Dean?) According to former Cobain/Love "manny" Michael DeWitt, you can see a scab in the video for Nirvana's "Heart-Shaped Box."
Disturbing? It probably feels worse for True, since one of his claims to fame is supposedly introducing Love to Cobain at a Butthole Surfers concert in 1991.
Watch the "Heart-Shaped Box" video yourself and see if you can spot the tell-tale scab.