The 53-year-old has had a difficult start to life at Camp Nou since replacing Luis Enrique in May, seeing one of his key men depart in a £200m move to Paris Saint-Germain and so far missing out on potential replacements, while also losing fellow forward Luis Suarez to a month-long injury.
Results have been largely disappointing, too, having lost 3-1 and 2-0 to Real Madrid in the two-legged Supercopa de Espana tie this week, but Valverde insists that his men cannot afford to look back as they begin their La Liga campaign at home to Real Betis on Sunday evening.
"Injuries can happen, as with Luis Suarez, and I understand that losing to a main rival and not winning a title can cause disappointment," he told reporters.
"But the loss of Neymar was something sudden and surprising. It makes us change our plans a bit. We must work in another direction to rearm ourselves. We have to step forward and not look back."
Barcelona are unbeaten in their last 12 league games against Betis, winning 10 and drawing the other two.