He looked at the place where his left ear should be, but all Mark Dacascos saw was a hole. It was surreal.

Whenever the veteran actor looked at himself in a mirror, the face that stared back was horrific: a mottled landscape of seared flesh and skin curdled and blistered by fire. There were gashes to the bone. Blood, too.

His reflection grew more disconcerting each time Dacascos looked. For nearly five hours, it kept getting worse.

But it wasn’t his face. It belonged to the "Hawaii Five-0" character Wo Fat, the terrorist played with steely menace by the Honolulu-born Dacascos on the CBS drama.

If this were real and not the work of a talented makeup team and an Oscar-winning makeup artist, Dacascos would have passed out screaming. But there was no pain here, only amazement.

"You look in the mirror and go, ‘Whoa,’" Dacascos said in a telephone call from Los Angeles. "I know it’s fake, but I look in the mirror and think, ‘Wow, this looks real. You get 6 inches away from the mirror and go, ‘Where is my ear?’ And I have a melted eyelid.’"

It was the most startling look any character has had since the show was rebooted in 2010. Three times during the show’s past season, including the last scene of the cliffhanger finale, the 49-year-old Dacascos was transformed.

When the curtain rises on the fourth season this week — on Thursday for those who attend the Sunset on the Beach advance screening in Waikiki and Friday for network viewers — Wo Fat will return in all his gory glory.

Regular viewers know the villain’s story from Season 3: Wo Fat suffered serious burns in a helicopter crash in Episode 21, which was shot at Kualoa Ranch with guest star Aisha Tyler. The "Five-0" cameras shot burn victim Dacascos after the crash and in another scene later at a hospital. In a prison scene in the season finale, he was recovered but horribly disfigured.

Until that point the Wo Fat character was not unlike a panther, silky and lethal, a killer in a tailored suit. But his burns revealed the monster within.

Peter Lenkov, executive producer for "Five-0," said he wanted Wo Fat to be a physical train wreck.

"I wanted him to look like he had acid poured on the side of his face, as if he had been burned," Lenkov said. "I wanted half of him to be destroyed. And the guy is a little bit of a monster and now that side of him comes out. Aesthetically, his exterior matches his interior."

The overall look of Wo Fat is the work of Jeff Dawn, a 54-year-old, third-generation Hollywood makeup specialist who won an Oscar in 1992 for his work on the Arnold Schwarzenegger film "Terminator 2: Judgment Day."

Dawn’s work on Dacascos was so good that when he showed photographs to a burn specialist at Straub Hospital, the doctor gasped.

"He said, ‘My God, this looks real,’" Dawn said. "‘If this man was brought to me I would start treating him.’"

Dawn has been the head of the "Five-0" makeup department since midway through the show’s first season, but he’s been in the industry for 33 years, most of it on feature films. He’s always on set when the "Five-0" cameras are rolling, supervising his makeup crew and working personally on the show’s core stars.

The Wo Fat burn project took extra preparations and even a test with an actor whose only role was to be a human canvas for Dawn’s designs.

When Dawn found the right look, he re-created it on Dacascos, gluing prosthetics made of silicone, gelatin and latex rubber to the actor’s face and upper body. It’s like playing with a Mr. Potato Head or the papier-mache art projects he made as a boy.

Dawn used an alcohol-based temporary tattoo ink as well as pigmented powders and creams to create the right colors, then applied them with an airbrush, a paintbrush and sponges.

"You are putting on the silicone and gelatin and latex pieces along with tissue paper and paper towels dipped in latex, which then hardens into rubber," Dawn said. "And you can tear the skin and paint it. You can make it look gooey and bloody. Fresh, open skin to black, charred skin that is almost coming off."

Wo Fat’s prison scenes with Steve McGarrett, played by Alex O’Loughlin, required a less severe but still ghastly, scarred look. When Dawn read the script, he was genuinely delighted: It was full of tight close-ups.

"That you have that kind of screen time where the audience is sitting there studying the eyebrows and the neck and the earlobes and the hands — that’s heaven for a makeup artist," he said.

Because he’d thought through the design, Dawn needs only to pop into the makeup trailer for periodic checks, but the application process can take several hours to complete.

When Dacascos shot the first episode of the new season back in July, he had to be on set by 8 a.m. That meant he had to be in the makeup trailer by 3:30 a.m.

But the lengthy process helps Dacascos get into character, especially when he looks in the mirror, he said. Seeing the injuries forces the actor to think of what he should be feeling.

"Whenever I look in the mirror, I see Mark but I also see this character and it’s weird," Dacascos said. "And then as a character I’m going, ‘If this is actually happening to me, if this is what is on my person, how does it feel?’ I shift in and out of that during the whole makeup process."

The real fun begins when it’s time to act, Dacascos said. That’s when the makeup brings him closer to Wo Fat.

"It doesn’t feel good and that’s good because that helps me as an actor," he said. "It helps me move the way I think he would move being that injured."

The actor doesn’t have to see himself anymore to know what he’s become.

Dacascos can feel the makeup and the glue on his skin. He can feel the texture and the sticky parts and then he clicks into character.

"All you have to add to that," he said, "is the pain."