The France international was fined £90,000 ($112,000) this week for turning up two hours late to a training session on Sunday, following the 4-0 win over Espanyol.
Dembele answered his critics with a fine solo goal inside seven minutes at the Camp Nou but Valverde is not ready to let him off the hook just yet.
"He has made a great goal, possible for players with his talent," said the Barca boss.
"We are happy with him and we said that throughout the season things happen that we try to solve internally.
"We hope that he and the rest will continue to give us much joys.
"I do not know [if the case is closed], tomorrow we have training."
With Barcelona already assured of top spot in Group B, Valverde made seven changes from the weekend win for the visit of Spurs.
Luis Suarez and Gerard Pique were among the senior players to miss out, while Lionel Messi was left on the bench and only played the last 27 minutes of the 1-1 stalemate.
And the club's two upcoming games was key to Valverde's decision to holding Messi back.
"It's better for him to play for a while and to be in motion, he likes it, we also and I don't have to tell you about the fans," he added.
"There have been players who were not there because we had an intense match three days ago.
"We wanted to see players like (Carles) Alena or (Juan) Miranda in difficult situations, as well as the response of (Jasper) Cillessen, (Thomas) Vermaelen, Arthur or Munir.
"We did not want to lose our competitive level against a very strong team."