Back on Earth, he was lobotomized.
It was Rekall. The whole movie was predicted near the beginning and again by Dr. Edgemarr (sp?).
The only part that hints at it being real is when the doctor says she hasn't implanted him with the ego trip yet and Arnold is out cold, but that's probably just part of the ego trip. It's a bit fishy that Arnold is out of it, or so it appears. Maybe he was just heavily sedated/dazed but still conscious.
Either way, the beginning part where they're talking about the ego trip Arnold is getting implanted with, they all refer to several key moments in the movie and Edgemarr further mentions more stuff.
Also, Paul Verhoeven himself said he thought and intended the movie to be interpreted as his ego trip.
It's not real. It's Rekall.
Ps. Arnold could have imagined the sweat, or maybe the doc just feels pressure considering he has a man's life in his hands. The sweat doesn't confirm it's real at all.