I have no boxing experience or training. I haven’t been in a fight of any kind since jr. high.
What would happen, medically, if I got in the ring with Lennox Lewis (or any pro boxer, for that matter) and he punched me in the face and head? Would I even live to see a rematch?
My Tale of the Tape: 5’11" 175lb. of flabby, average white dude.
A better way to phrase the question is, “What if I looked like Mike Tyson to Lennox Lewis and he punched me in the face as though he was trying to knock me out with one punch?”
Result: At best, you would be knocked unconscious for an indefinite period of time. There may or may not be after effect such as headaches and dizziness. You would have suffered a bad concussion. At worst, you would never regain consciousness, suffer a brain hemmorage and die. Boxers actually develop a tolerance to being hit. Their brain conditions itself to recovering from blows to the head. Of course, over time the results of this can become apparant in the syndome of being “punch drunk”.
It’s never good to get hit in the head. Maybe the best example is someone who has hit their head in an automobile accident. Some people recover quite nicely, others need a lot of rehabilitation.
After you got out of the hospital, you would probably sue him. 
You’d probably live, but a lot of it has to do with how you got hit and your individual ability to “take a punch” and not lose consciousness, which is not necessarily to related to being in fantastic physical shape win the case of a head shot. If you were hit while not expecting it you might well be injured far worse than if your body was expecting the blow (as a boxer would) and was prepared to take the hit.
This is hypothetical, right? 
::raises hand:: I’d laugh, then take pictures.
'Course I’d share 'em here.
Let’s consider Lennox’s stats:
Height: 6’5"
Weight: 240
Chest: 46"
Biceps: 17"
If he wore a glove, you would wake up in hospital at best.
If he wasn’t wearing a glove, you would wake up in a place with lots of clouds and angels with harps.
I’m pretty sure Tyson will never fight again, after the biting fiasco and the no-show fiasco.
The Lewis punch might possibly kill you if he hits you in the nose or chin. If he hits your forehead, you might get sleepytime for a bit and Parkinson’s in your old age. Helpful hint: Kick him in the balls while he’s winding up for the big payoff punch.
Huh? He fought about a month or two ago, and is working on lining up more fights, as we speak.
I know Flymaster beat me to it, but do you want to put some money on that?
I sincerely doubt Lennox Lewis has a GOOD chance of killing you, gloveless or not. He’s a tremendous puncher, but if you could kill people with punches that easily, people would be dropping like flies. Lots of people nearly as strong, or as strong, as Lennox Lewis get into bar fights are whatnot, but it’s awfully rare that they kill each other. Lewis’s success as a boxer has less to do with his raw punching power, which lots of beefheads have, and a lot more to do with his boxing SKILLS, which are vastly more advanced than anyone you’ll find in a tough bar. ONE Lewis punch will not kill you or give you Parkinson’s.
If Lennox Lewis punched you full in the face, the extent of injury would depend where he hit you. In any case you’d likely be pretty stunned by the blow, suffering a mild concussion. If you were really unlucky, he’d hit you in the jaw and break it, or break some teeth. A blow around the eye could possibly fracture the orbit. If you were slightly luckier he might break your nose. If you were really lucky you’d suffer no injury other than the concussion.
Your odds of dying or being put in a coma are very, very small.
Hits to the side of the head are more damaging, the brain can take quite a knock front to back, but not sideways.
After you’re recovery from the concussion and attendant tissue damage to your face, you could retire on the losers purse.
See the Jackass movie for a realtime account of what happens when a regular shmoe goes up against a trained fighter.
Johnny Knoxville (regular shmoe) fights Butterbean (badass) and, IIRC, after about 15 or 20 seconds Knoxville is out cold with a concussion and then heads to the hospital for stitches.
I’d reccomend you stay away from Lewis if you have reason to suspect he wants to hit you :).
Sorry answer but:
“It Depends”
If you had trained in boxing (i.e. strong neck muscles, knew how to “take” a punch - in other words knew how to duck or minimize impact) then it wouldn’t be soo bad…
A completely clueless, unsuspecting skinny white guy getting a full on right arm from Lennox on the chin? Broken jaw, concussion, probably some fractured neck vertebre…maybe death…
Like I always said “I’d fight Mike Tyson or Lewis fo $10M…I guarantee I can hit the canvas faster than they can run accross and hit me…”
Just my two cents…
Daylon
I’d probably fight Lewis for $10M, but only because I think he’s enough of a gentleman not to kill me. Tyson, on the other hand, doesn’t exhibit much self control, and I would expect him to snap my pencil-like neck with the first punch. Not that Lewis couldn’t do the same, but I think he probably wouldn’t.
I once had a pretty painful whiplash-style neck injury after being punched in the face by a scrawny little guy–at least a foot shorter and a hundred pounds lighter than Lewis. I didn’t see it coming, wasn’t prepared at all, plus, as mentioned before, I have a pencil neck. A big, well-trained puncher could do a lot more damage than that. I wouldn’t be surprised at all if Lewis could break my neck with one punch. It’s pretty rare, but not unheard of, for trained fighters to die as a result of injuries in the ring.
!. Pain.
2. Lawsuit.
3. Kick-ass bragging rights.
I got a full-on, nothing held back, (accidental) roundhouse kick from a taekwondo black belt. My head was padded, though his heel was not. Literally sent me in the air across the room. Gave me a mild concussion and a sore neck, but that was all.
Actually was kind of fun after it wore off.
“So that’s how hard Sun-seng-nim kicks…”
Hmm… “trained fighter” = Butterbean 
Sorry … Butterbean’s a tough, badass brawler but a “trained fighter” he ain’t. 53 year old Larry Holmes kicked his ass in a match a year or so ago.