Lamela and Schlupp came together as Palace went on the attack.
But the pair fell awkwardly on the floor and Schlupp’s boot appeared to come down and hit the Argentine in the face.
Blood immediately started pouring from the wound and he was promptly replaced by Harry Winks.
It is not yet known how serious the injury but he was brought off with what looked like a nasty gash on his head.
Early reports suggest he has been sent to hospital to be assessed.
Incredibly, the game was not immediately stopped by referee Jonathan Moss despite the rules surrounding head injuries.
Juan Foyth sealed all three points for Mauricio Pochettino’s at Selhurst Park.
The 20-year-old centre-back had a torrid time in last week’s 3-2 win against Wolves at Molineux as he gave away two penalties.
But Foyth made up for it as he reacted quickest to a loose ball after Palace failed to clear a corner to register his first-ever goal in the Premier League.
The win sees Tottenham solid their fourth place in the Premier League.
They are now four points ahead of fifth-placed s Arsenal and cannot be overtaken by their north London rivals whatever their reulst against Wolves on Sunday.
Spurs go level on points with Liverpool and Chelsea and are only two points behind leaders Manchester City.
However, all three have a game in hand and play on Sunday, with Liverpool hosting bottom-of-the-table Fulham at Anfield.
Chelsea are at home to Everton, while City welcome neighbours Manchester United to the Etihad.