Euans's international career has been on hold for the past 17 months and he admits he considered quitting the game.
But the popular prop has explained how God helped him cope with his bad luck and he is relishing winning a second cap against Romania at Murrayfield this weekend.
The forward said: "I always suspected that all my injuries were due to the way I was leading my life, and after getting a nasty concussion which led to me suffering a seizure on the pitch against Munster last September, I thought maybe I should change.
"So I started trying to change my life and I found I couldn't really. I started going to church but it didn't make any difference.
"Then I heard the gospel which is the good news that Jesus Christ died for our sins, and realised that I had to believe that with all my heart.
"This faith was a major factor in my decision to carry on playing rugby. Rugby was where I found myself and I've been blessed with a whole load of talents that I have to use to the best of my ability.
"I seriously considered walking away from the game. It was an avalanche of injuries and there didn't seem to be any way out, but I thought I'd give it another chance - as I always have done because I don't like to quit - so I just kept going, and now here I am, this feels like I'm being rewarded."
Euan made his international debut as a replacement during Scotland's 39-19 victory over Romania the last time the two sides met in Bucharest in June 2005.
After that, however, he suffered a torn quad muscle, a severe concussion, a neck injury and an Achilles problem in quick succession.
"It was a difficult year," he added. "But the big thing is that I'm now much happier and at peace with the things that are going on in my life.
"I felt I was leading an immoral lifestyle. I don't know if it contributed to my injuries, but whatever the case I'm here now and I know the truth."
Glasgow and Scotland supporters will be relieved to hear that this new-found inner-peace will not be reflected in his approach to Saturday's match.
"I still like to go out and smash people," he said. "There's nothing wrong with that. It's one of my talents.
"It's been a long time since I've been involved with Scotland. It is roughly 18 months since I played and I was coming off the bench that time. So to get a start is really like my first cap."