“Have you ever had to kill people because they already killed your friends and are coming for you next? Have you ever done things that made you afraid of yourself afterward? Have you ever been covered in so much blood that you didn’t know if it was yours, walkers or your friends?"
See there, Michonne is foreshadowing what happened to Glenn. He had the blood and guts of Nicholas on him. The scene shows only Glenn grimacing, not actually being bitten.
I am sure that Glenn ducked under the dumpster and snuck away to safety. Remember, Glenn is the resourceful one. He knows better than anyone how to avoid the walkers. For God's sake, he was a pizza delivery guy in a previous life.
Glenn is still alive.
LURKING, WE CONTROL YOUR TV SET ON THE GRASSY KNOLL
