The Welsh international wasted a golden opportunity with the Reds leading 2-1 at Goodison Park, and they nearly went on to lose after Romelu Lukaku netted twice to put the Toffees 3-2 ahead.
"Things can get taken out of perspective in the intensity of a game like the derby, and a lot of people probably wrote me off the second that game finished," the 23-year-old told The Mirror.
"I feel it was something that would have affected me in the past but, in all honesty, it didn't really affect me too much. I was able to look at it as one moment in one football match.
"I understood the significance of it, of course. It was a pivotal moment in a massive game and there is no hiding from that. But I understood it was a miss and it happens in football."
Allen is yet to score a goal in the Premier League for the club he joined last year from Swansea City.