"I was waking up every morning with a headache, sore eyes, low energy and really not feeling up to much.
"But thankfully the doctors looked after me, I saw a few neurologists, had a few courses of medication and I've come right now.
"Everyone has cleared me and they're all happy that I'm playing again. There is no risk of me being more susceptible to concussion than there was before.
"It has been quite frustrating sitting on the side, especially for how long it took to get better again. But thankfully I've been looked after well off the field."
Lambie has recovered well enough to be considered for the Springboks' fifth match of the 2016 Rugby Championship this weekend at Loftus Versfeld in Pretoria on Saturday, despite having played just one provincial match for the Sharks in South Africa's domestic Currie Cup competition.
"I'm thrilled to be back, very excited to be included in the group again. I've missed being part of the Springboks, so it is wonderful to be back."
Lambie's return to the full fitness should be a welcome boost to the South African squad, who have had a dreadful outing in this year's Rugby Championship, accumulating just one win from four matches.
Although Lambie isn't expected to be named in the starting side, which will be named on Thursday, it is expected he may play some part in the match from off the bench.