The 22-year-old midfielder followed Brendan Rodgers from Swansea City to Anfield last summer, with £15million changing hands.
Allen has, however, struggled to display the consistency which drew so much praise during his time in South Wales.
He admits that he is yet to produce his best for the Reds but, despite losing his place in the team, is convinced that hard work for club and country will get him back on track.
Ahead of an international outing for Wales against Austria on Wednesday, Allen said: "My form hasn't been great.
"I'm a perfectionist and maybe that's my problem. Sometimes I get frustrated and disappointed when things aren't perfect.
"It's been disappointing not to have been involved in every game and play every game.
"But it's up to me now to work hard and get myself back in the team and improve my level of performance."