Cadamarteri, signed in the summer, scored on his first start of the season against Luton on Saturday.
He struck again midway through the second half and immediately dashed over to celebrate with Huddersfield fans in the main stand.
Referee Nigel Miller, who ruined the game with his constant interruptions, issued a second yellow card and Cadamarteri was off down the tunnel.
Cadamarteri, booked for an early foul, suffered a hamstring injury on the eve of the season and only returned to fitness two weeks ago.
Forest, now on the climb after a poor start to the season, were given a lifeline by Cadamarteri's red card and the ten men were under pressure.
They cracked in the 75th minute when sub Kris Commons unleashed a stunning equaliser from 25 yards.
The Forest players could not contain their delight either and four or five of them, including scorer Commons, crammed into the visitors' dugout to celebrate.
With the home fans furious, Mr Miller was forced to caution Commons for Forest's unusual celebrations.
Forest finished the game strongly and Town keeper Matt Glennon pulled off a fine stop from Chris Cohen ten minutes from time.
Cadamarteri lit up a dour game when he fired home from close range after Andy Holdsworth's cross-field pass but he turned villain with his sending off.
Mr Miller left the field to a deafening chorus of boos from the home fans.