The Glasgow Warriors wing was initially left out of the squad for the two-Test trip, but injury to Tim Visser resulted in a call-up for the 35-year-old.
Lamont made his Scotland debut in 2004 and turned out for the 104th time during this year's Six Nations.
"When I was left out I was absolutely gutted. To get the phone call again was very nice," he told BBC Scotland.
"I love playing for Scotland it's a massive part of what I've grown up doing for 12 years now.
"It's been a big part of my life and I sure as damn don't want it to go away."
Lamont may be close to Paterson's record but realises that with every passing Test the competition for places in Vern Cotter's line-up is greater, with younger players breaking through.
"Eventually it will have to finish but it's been a fairly emotional roller coaster," he explained. "The disappointment of not getting the call-up and then getting the call, so it's nice to still be on that list.
"If someone's ahead of me I like pushing myself to get ahead of them, that's the way it should be.
"But in the cold light of day it's down to the coaches to make the choice.
"I know where I am in my career, I'm all for pushing the next generation through - it's good for Scottish rugby, it's something we need, so the more competition it's good for the player and the country."
The Scots are unbeaten in five meetings with Japan, with the last encounter a 45-10 victory at the World Cup in 2015.
Japan are 10th in the world rankings, one place below Scotland, and Lamont expects two strongly contested encounters in Toyota City and Tokyo.
"They're going to be two tough Tests, no shadow of doubt," he said.
"They'll be geed up because of the run they had at the World Cup, they'll be looking to claim a scalp and boost the profile of Japanese rugby.
"Things like home advantage and weather, I think it'll be hot and humid over there, and above all they're a good team so we've got be very wary.
"They pushed us in the World Cup for a good 60 minutes, but towards the end we ran away with it, but it was by no means easy, there were some real sticky moments."
BBC Scotland will provide live television, online and radio coverage of the Tests on 18 and 25 June.
Sean Lamont aims to take a step closer to Chris Paterson's Scotland cap record of 109 on the summer tour of Japan.