The on-loan Southampton striker has now scored eight goals in 18 games since joining Forest with his pair guiding the club to eighth position on the Championship table.
The 26-year old then made it 2-1 less than ten minutes into the second half when he rounded Kenny before Rodolpho Austin's own-goal gave Forest a two-goal advantage.
Dexter Blackstock made it 3-1 just after the hour-mark before Leeds got one back through Davide Somma very late on.
"I just hope Tom learns from the incident - it is a harsh lesson for him but one he's got to make sure doesn't happen again," he said.
"I've known Billy a long time and if you are up against him in the area he's going to be clever.
"Tom has just breathed on him but Billy has made sure there is contact and gone down. In that situation you have got to stand a yard off him.
"It's a penalty because 20 out of 20 referees would give it. Billy used to get penalties for me like that at Sheffield United so I can't complain. Tom has just got to be more professional."