No he hasn't. Blair has stayed on and on in office, disregarding opinion in his own party and on the streets and (unless he has to step down over corruption charges unrelated to Iraq) will depart later this year at a time of his own choosing.
After which he will travel the globe, play at being an elder statesman and rake in the appearance fees.
His career hasn't suffered in the least.
What he has sacrificed is his reputation.