The Northern Irishman boss believes that the Blaugrana forward made too much out of the clash that saw the Bhoys captain sent off just before the hour mark
The Bhoys skipper was sent off in the 59th minute of the contest in Glasgow for kicking Neymar in the back, after he had brought the attacker down in an attempt to prevent the Brazil international from surging forward.
Barcelona went on to capitalise on their numerical advantage, Cesc Fabregas heading home Alexis Sanchez's cross 14 minutes from time, with the goal coming shortly after James Forrest and Charlie Mulgrew had both gone close at the other end.
Lennon was quick to denounce referee Stephane Lannoy's decision to show Brown the red card, and felt that Neymar's reaction to Brown's kick was unnecessary.
"I'm not convinced it is [a red card], if there is any contact, it's minimal. It changed the game, it's hard enough playing Barcelona with 11 men," the Northern Irishman told ITV Sport.
"He [Neymar] has a reputation in the game, he's a brilliant player, but sometimes he exaggerates things a little."
Fraser Forster produced three excellent stops to prevent Barcelona from adding to their lead in the closing stages, but they were to left to rue the missed opportunities that ultimately cost them at least a point.
"I can't speak highly enough of the players," Lennon added.
"There was a brilliant save from (Victor) Valdes and Charlie should do better with the header.
"I didn't remember Fraser having a lot to do but then he pulled off three great saves. Valdes had to make the better saves."
Celtic's defeat has left them bottom of Group H, with two defeats from two games played.