Byrne was fined and banned for his part in the '16th man' saga that marred the Ospreys' Heineken Cup win over Leicester Tigers on January 23 but he has since had that suspension overturned.
The 29-year-old Lions tourist, who started the first Test against the Springboks last summer before injury brought his tour to a premature end, admitted that fighting the ban had been a draining experience.
"I found myself in a difficult position, but I'm just glad it's all over now," said Byrne after he was cleared to face England at Twickenham this Saturday.
"I'm absolutely over the moon to be honest. I'm just glad to put the last four or five days behind me and be back on familiar ground preparing for a game of rugby rather than thinking about an appeal hearing.
"All thoughts of the case are now immediately out of my mind. I've missed one training session in getting to Glasgow, but we are at the business end of the training week and all my focus now must be on Twickenham."
Byrne hasn't played international rugby since the Lions' defeat to South Africa in Durban on June 20 after injury ruled him out of all four autumn internationals.
And, having been one of the world's leading performers in 2008 and 2009, the 27-cap star is unsurprisingly desperate to return to the big stage.
"It's just going to be great to get back to international rugby. It feels like I've been away for ages after missing out on the autumn internationals due to the injury I picked up with the Lions," added Byrne.
"I found it very difficult to watch the boys in the autumn and ended up going away on holiday because I'm not a great watcher.
"I'm really looking forward to getting back on the field at Twickenham and there's nothing like starting back with the big one against England in a centenary game.
"The expectation at the start of any campaign is immense but the senior players in this squad have been through a lot together now, we have the experience and we have just got to handle that pressure - we know we can do it."