The 18-year-old winger struck Rovers' winner in a 2-1 comeback victory at home to Derby County on Friday night.
Mowbray told the Lancashire Telegraph: “Harvey is a wonderful talent. I don't want to keep eulogising about him, because the statistics and his quality on the ball stand out for all to see.
“If anything, we can't get the ball to him enough, but when we do, in and around the box, he can produce quality like he showed.
“I did tell him before the game that he has to keep his goal tally ticking along, although he seemingly gets an assist every game, but we're delighted for him because he needs to keep it ticking along for his own confidence and belief, not that he's short on that, because he's a wonderful talent.
“I'm delighted for him and you could see his own delight in his celebration."