Scotland, who scored moments into his Tykes debut in last weekend's 2-0 win over Millwall, sealed three points in the 88th minute after his initial shot was saved by Blackpool's substitute goalkeeper Mark Halstead.
Matt Gilks' red card for deliberate handball brought Halstead into the action at a time when the managerless Seasiders were in the ascendancy.
Jim O'Brien sent Barnsley in ahead at the break, the 20th time in 30 league games Blackpool have conceded the first goal this term, but Tom Ince deservedly levelled matters with his 16th of the season after 55 minutes.
Pool appeared the most likely winners despite being a man down and Matt Derbyshire rattled the crossbar before Scotland has the final word.
Barnsley move to within two points of fourth-bottom Wolves and are six behind their opponents in 15th.