Care was axed from England's Six Nations squad after he was arrested - and subsequently convicted - for drink driving in the early hours of New Year's Day.
The shock of losing his England place forced Care to get his priorities straight and his late-season form was integral to Harlequins' Premiership title triumph.
Care made his England comeback in the third Test against South Africa on the summer tour and produced a man-of-the-match performance in a 14-14 draw.
The 25-year-old is expected to keep his place ahead of Ben Youngs when England launch their QBE autumn campaign against Fiji at Twickenham on Saturday.
Care believes the whole episode, as tough as it was at the time, has made him a better person and a better player.
"It's all about rugby for me now. That's what I lost sight of a bit last year. I let my standards slip," Care said.
"I've learned an awful lot in a short space of time. I had to grow up pretty quickly and I think I've done that.
"Playing for England is the biggest honour you can ever have. To have that taken away hurt me a lot. I'll never do anything to put myself in that situation again.
"It was my fault. I put Stuart Lancaster in a position where he had to do something and he did. I understood his decision.
"Stuart said to me that day 'by no means is your England career over, you've just got to get yourself back on track, get playing well and you'll be back in my thoughts'.
"That's what I've done.
"I'm just delighted to get another chance with Stuart. I've worked with him since I was 14. He told me off back then, he still tells me off now."
Care's renewed focus has led to a more professional approach to his training and the analysis he now does on every performance, part of a constant drive to be the best he can be.
By his own admission, that was missing 12 months ago but the advice of former England scrum-half Kyran Bracken and his rivalry with Leicester's Ben Youngs has brought it into sharp focus.
Bracken spent his whole 51-cap England career competing with Matt Dawson and Andy Gomarsall for the scrum-half position and Care taps into his expertise with regular training sessions.
"From speaking to Kyran, it's about playing well every game. I know every time I pull on a Quins shirt I have to do that, because Ben wants the same England shirt," he said.
"A couple of years ago I'd go a couple of good games then have a bad game.
"I've matured as a player as well. You only get better by playing in the biggest games and I'm lucky to have played in a Premiership final as well as Test matches in New Zealand and South Africa.
"Games like that define you as a player. You grow from experiences like those.
"Ultimately I want to be the best scrum-half in England. That's my aim. To do that I've got to train and play very well every time I get the chance, because the England shirt can be very quickly taken away from you."
Lancaster will confirm his starting XV to face Fiji tomorrow morning, with Care likely to partner Toby Flood in the half-backs with a licence to attack.
"Stuart told me to carry on the way I'm playing, to bring that energy and tempo to the game. He wants an energiser at nine, he wants someone to play quickly," Care said.
"We've got to be calculated in what we do - but I think the gameplan's going to be similar to a Quins one. If it's on it's on, otherwise rely on a good kicking game and a good chase.
"It's music to my ears really."
Leicester hooker Tom Youngs is expected to be given his Test debut in the injury absence of Dylan Hartley, while Thomas Waldrom is in line to start at number eight.
Tom Johnson is the incumbent blindside flanker but Tom Wood returns to an England squad for the first time in 14 injury-plagued months.
The uncapped pair of Saracens prop Mako Vunipola and Wasps lock Joe Launchbury are both in the 23-man squad.
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