The Lotus driver was hampered by back pain, a legacy from a 2001 testing crash, ahead of qualifying for the Marina Bay event.
Raikkonen could only qualify in 13th place as a result, but went on to finish on the podium in the race.
The Finn said he was feeling better now, but admitted he will be unsure about his form until he takes to the track next Friday.
"It's better than it was on Saturday in Singapore which is when it didn't feel too good," said Raikkonen. "The important thing was that I was able to race and we did a pretty good job with the podium finish.
"It's not the first time I've had a problem, as there have been some issues with my back for a long time.
"We will have to see how it is when I get out on track on Friday in Korea."