Terry had opened the scoring in the Premier League clash on Sunday but was carried off on a stretcher following an accidental collision with Luis Suarez, who scored the equaliser in the second half.
The Chelsea skipper, who was returning from a four-match domestic ban for racial abuse, immediately signalled concern to his bench when he went down and will have a scan on Monday to determine the nature of the injury.
"We have to wait until his MRI scan to understand the full extent," said Di Matteo. "There's concern. We just got him back into the team after the ban.
"It was great seeing him out there. We hope it's not a serious injury, but we'll see. When a player reacts like that, it's a concern. He's in pain now."
Terry opened the scoring in the 20th minute when he powerfully headed home from Juan Mata's corner for his 50th Chelsea goal.
"He started the game very good, showing the qualities he has, and the experience and influence," Di Matteo said.
"It's a real shame he had to come off as he was having a very good game. We hope it's not long-term."
Chelsea had chances to seal the game but Brad Jones denied Fernando Torres and Mata was guilty of wasting opportunities either side of half-time.
Liverpool punished the hosts 17 minutes before full-time when Suso's corner was flicked on by Jamie Carragher and Suarez evaded Ramires to nod home.
Di Matteo said: "It was a poor goal to concede. We had man-marking for the opposition and Ramires was with Suarez and he pushed him away to create that bit of space for himself to nod the ball in.
"Sometimes the refs notice. Sometimes they don't. It's one of those."
Chelsea have now failed to win in their last three Premier League games, having seen previous title attempts falter at this stage of the season before.
But Di Matteo added: "We're in much better shape than in previous years, in a much better position, and very close to our best.
"If we had won this game, it would have been great for us. We're still in the mix. But the amount of games you play in this period has some kind of effect."
Di Matteo also suggested that ex-Chelsea striker Didier Drogba will be allowed to train at the club's Cobham headquarters ahead of the Africa Cup of Nations in South Africa, which starts in January.
"He's a legend at this club, a real pleasure to work with," Di Matteo said.
"If he needs any help from us, he'll always be very welcome in our club."
Liverpool coach Brendan Rodgers believes his team need investment in players to compete at the top of the Premier League.
"We need one or two more players. That's our sixth draw. And a lot of those games we've come back into after going behind," he said.
"We're normally dominating games with the ball. But we need materials. If we can get one or two (new players) in January, we'll turn draws into wins.
"The reality is we're a long way off in the league. I'm not going to say the word 'challenging'.
"You don't need to be a rocket scientist to see the squad -- these guys are giving me everything.
"If we can get one or two players to make the difference for us -- look at Chelsea, with (Eden) Hazard, and their investment. We don't have that, so we have to grow our own."
Rodgers said Steven Gerrard should be fit to earn his 100th international cap when England play Sweden in a friendly game on Wednesday, despite needing attention to his knee in the second half.
Jonjo Shelvey also missed the game with a thigh problem.
"I think Steven will be all right. He's opened up his medial ligament a bit and has some ice on his knee," Rodgers said.
"With Jonjo, we wanted to give him an opportunity right up to the end. He was in some shooting exercises in training and felt his thigh a bit.
"But he'll meet up with England, they'll look at him, and we'll make a decision from there."