Hughes was out for five months after what he describes as "a bad knockout".
"At the start, when I was really struggling, the thought does go through your mind and you have to battle against those thoughts if you want to come back," said the 26-year-old.
"But the last four months have been really good."
Hughes returned as a wing replacement in Friday's 34-10 European Challenge Cup win over Siberian side Enisei-STM.
He said the club and their medical team had been "amazing" during his time on the sidelines, adding: "I can't thank them enough. They haven't rushed me, which is key with concussions."
Hughes is in his second spell with the Welsh side after a season at Exeter Chiefs and a loan period at Bristol.
