Here's a partial list from my files: (Not all are facial injuries though)
Number of stitches are approximate and depends on the source.
310 – Clint Malarchuk (Jugular vein cut by Steve Tuttle)
250 – Borje Salming (above right eye,nose and side of face, Nov.27,1986 - Cut by Gerard Gallant’s skate)
200 – Mikael Renberg (1997, Philadelphia)
200 – Vladimir Vujtek (Oct 1999) (Cut his cheek by a skate from Valeri Kamensky)
145 – Helge Bostrom (1931 skate cut 3 of the 4 tendons in his L leg-collision with Earl Seibert)
120 – Aaron Gavey (1996) (Took a skate to the face by teammate Michel Petit)
115 – Dan Bylsma (1999 – a shot that shattered his orbital bone face broken in 11 places)
88 – Scott Stevens (Apr,21,1989, Swe vs Can - Cut by Borje Salming’s skate)
84 – Jay Pandolfo (Jan,2000) (Checked by Mathieu Dandeneault)
80 – Rick MacLeish (Neck severly cut in 77-78, Phi vs LA - Cut by Marcel Dionne’s skate)
70 – Darryl Sydor (puck hit lip and left side of nose, Jan.29,2006 ,TB at Phi)
66 – Paul Boutilier (Shot in forehead by Tomas Jonsson (or Anders Kallur?). Nov,1984 at NYI training)
62 – Kjell Samuelsson (High stick to face, 1995 Pit vs Wsh - Michal Pivonka high stick)
60 – Bruce Shoebottom (Laceration on right side of his face after Tom Martin accidentally skated over his face during Maine's Nov. 29, 1989, AHL game vs. Binghamton)
60 – Ryan Smyth (Fractured jaw, Mar.10,1999, Edm at Dal - Struck by Boris Mironov shot)
52 – Jeff Carter (Puck hit left ear, Dec.17,2004, Van vs Phi)
50 to 100 – Ian Laperriere (2009) (Returned in the 3rd period - Hit by a puck)
50 to 60 – Viktor Stalberg (Hit by a Ryan Getzlaf shot)
50 to 60 – Drew Miller (Struck in face by skate)
50 – Adam Graves (Deep cut inside his mouth, May 1,1996 - Practice,Mike Richter clearing)
50 – Aleksey Morozov (Sliced ear, 2003 Pit vs Atl)
50 – Andrei Zyuzin (Jan,2006, Min - Checked into boards face first)
50 – Craig MacDonald (Dec,2007 - Hit in the mouth by a Hal Gill wrist shot)
46 – Denis Owchar (Head wound, Oct.20,1976, Tor vs Pit - High stick from Tiger Williams)
44 – Martin Havlat
42 – Ed van Impe (Puck cut his lip for 35 and tongue for 7)
42 – Brendan Shanahan (Cut above his right eye, Det vs Col - Checked by Peter Forsberg)
41 – Bruce Driver (Above right eye,Dec.23,1990, NJ vs Tor)
41 – Robert Svehla (Playoffs, Fla vs Phi - Cut by Eric Lindros skate)
40 – Todd Fedoruk (Gash on his head, Dec.21,2002, Phi vs Ott - Checked by Mike Fisher)
40 – Kris Draper (Checked from behind, 1996, Col vs Det - Checked by Claude Lemieux)
40 – Paul Fenton (Cut on forehead, Feb,1992)
40 – Doug Gilmour (1993, Tor vs LA - By Wayne Gretzky)
40 – Garry Galley (Cut on cheek,lips,neck, Oct.6,1990, Bos vs Que - Cut by teammate Randy Burridge skate)
40 – Chris Chelios (laceration of left temple, Feb.9,1991, Chi at Bos - Cut by Bob Sweeney’s skate)
Other ones that comes to mind, although not all being facial injuries:
Kevin Stevens falling to the ice face first, needing major reconstructive surgery
Richard Zednik, getting his throat slashed by Olli Jokinen's skate in 2008
Randy Pierce was out for a while in 1980 or 1981 with a fractured nose and cheekbone as well as contusion in his eye. He was hit by a puck and required plastic surgery to repair his cheekbone and nose. The following season he got another nasty injury resulting in a concussion and facial lacerations on his forehead and eyelid, resulting in around 20 stitches.
Stu Kulak who had the top of his ear bitten off during a fight in an exhibition game against a touring Russian team in 1995 or 1996. He needed several stitches to re-attach the ear and a tetanus shot.
I am sure there are many other examples of serious facial injuries over the years.
There have been some gruesome facial injuries outside of the NHL.
The worst one was probably the injury to a Polish player at the 1972 World Pool B Championships.
A player by the name of Feliks Goralczyk had an opponents skate stuck to his face and it took several minutes for both team doctors to gently separate the skate from his face. He was transported to a local hospital, but lost the sight on the eye.