Magpies midfielder Jack Crisp was also cleared of wrongdoing over a sling tackle on the Bulldogs' Rhylee West, keeping alive his bid to break the record for most consecutive AFL games played.
In the fourth quarter of Collingwood's thrilling 10.16 (76) to 10.10 (70) win at the MCG on Friday night, Cox marked on the wing and Lobb's late spoil caught him flush on the cheek, flooring him.
The Collingwood ruck-forward was unable to take his kick and did not see out the game, while he had swelling and cuts under his eye.
"He looks like he's got a couple stitches in his eye," McRae said.
"Didn't come back on the ground, but I'm not too sure we're too concerned about that. But we'll have to monitor him in the next period.
"It looked on the vision like he got punched in the face, so he got a couple of stitches."
Collingwood have the bye next, so Cox should be fit to face Carlton in round four.
Asked if he expected the incident to get looked at by the match review officer, McRae said: "I'm not sure, I assume so.
"Guy leaves the ground with a couple of stitches, I'm not sure. I'll leave it up to others to decide that."
On Saturday, the AFL confirmed the match review officer had looked at the incident and decided Lobb had no case to answer.
"It was the view of the MRO that Lobb made a genuine attempt to spoil and that it was not reasonably foreseeable his actions would result in a reportable offence being committed," the league said in a statement.
"No further action was taken."
Cox wears special sports glasses to protect his eyes after multiple surgeries earlier in his career.
Asked if the damage was done by his glasses, McRae said: "Potentially. But he got punched in the face."
Crisp gave away a free kick for his dangerous tackle on West in the first quarter, but was also given the green light by the match review officer.
A suspension would have ended Crisp's extraordinary streak of 240 consecutive games, which is four shy of the late Melbourne legend Jim Stynes' record.
Collingwood forward Beau McCreery was fined $1500 for misconduct against Lobb, who sported distinctive blue hair on Friday night.
The fine can be reduced to $1000 with an early guilty plea.
Bulldogs midfielder Ed Richards was fined $1000 for careless contact with an umpire.
26°C