Pienaar clashed heads with compatriot Bongani Khumalo when both players went for a high ball during training last week at Spurs.
"It's funny because the headaches go away and then they come again. I'm still taking some tablets," Pienaar told Reuters on Tuesday.
Pienaar trained on Monday and Tuesday and said he was available to play against Kenya at Rustenburg's Royal Bafokeng Stadium on Wednesday.
The midfielder joined Tottenham Hotspur from fellow Premier League club Everton during last month's transfer window and said he was looking forward to the prospect of a return to Champions League action.
He last played in Europe's top club competition at Dutch club Ajax five years ago and is hoping to feature next week when Harry Redknapp's side travel to AC Milan in their last-16 first leg match.
"I'm looking forward to every game, also the Champions League. It's every player's wish to compete there at the highest level and to have that opportunity at the age of 28, I consider it an honour," he said.
"The move is something new, it's a new club, a new city. You have to get used to your surroundings.
"Time will tell if I made the right move, for me it's a challenge, that's why you play football, for the challenges. You have to take risks and that's the risk I took."
