scotch game
There are many voor books and dvd,s for the Black side of the Scotch. I for example like Jan Gustafsson's DVD from chessbase. However as you yourself explain your problem is probably nog the opening but tactics/blunders so i recommend tactics trainers.
I'm not sure but I think Karpov analysed a Scotch game position with nice insights in a Dzindzishachvili's video available on youtube.
PS: Sorry I'm definitely unable to spell Dzindzi's name.
The OP has stated they want a line as Black. One such is 4...Bb4+ 5.c3 Bc5. By interpolating the bishop check Black encourages White to play 5.c3 taking away the best square from his QN. On 6.Be3 Black retreats 6...Bb6. You can look up this position in the databases, or maybe a titled master will weigh in on this thread.
It gives you flexibility too: after c3 you can withdraw the Bishop with ...Be7 instead of ...Bc5. Either way you also get a surprise element against your opponent.
It is mainly avoiding something, like 5.Nb3 for instance, in my opinion, 7.g3 can be also dangerous for Black, White can play c3 and on Be7 he can play Bc4 followed by Nxc6 and e5.
Possibly helpful:
Starting Out: The Scotch Game by John Emms (2005)
https://web.archive.org/web/20140627061119/http://www.chesscafe.com/text/hansen82.pdf
The Scotch Game Explained by Gary Lane (2005)
https://web.archive.org/web/20140627061119/http://www.chesscafe.com/text/hansen82.pdf
Beating the open games, Mihail Marin
https://web.archive.org/web/20140626195205/http://www.chesscafe.com/text/hansen102.pdf
Open-Games-Black-Igor-Lysyj
https://web.archive.org/web/20140627104938/http://www.chesscafe.com/text/hansen159.pdf
Play the Open Games as Black by John Emms
https://web.archive.org/web/20140627022601/http://www.chesscafe.com/text/hansen11.txt
Bologan's Black Weapons in the Open Games
http://www.jeremysilman.com/shop/pc/Bologans-Black-Weapons-in-the-Open-Games-76p3873.htm
Starting Out: Open Games by GM Glenn Flear (2010)
https://web.archive.org/web/20140626232452/http://www.chesscafe.com/text/hansen134.pdf
Play 1 e4 e5! by Nigel Davies (2006)
https://web.archive.org/web/20140626201436/http://www.chesscafe.com/text/hansen80.pdf
https://web.archive.org/web/20140627083715/http://www.chesscafe.com/text/hansen98.pdf
The Kaufman Repertoire for Black & White by Larry Kaufman (2012)
https://web.archive.org/web/20140626221508/http://www.chesscafe.com/text/hansen162.pdf
Opening Repertoire: The Open Games with Black by Martin Lokander (2015)
Playing 1.e4 e5 - A Classical Repertoire by Nikolaos Ntirlis (2016)