Doctors thought the strange, bleeding bumps on Aaron Dallas' head might be from gnat bites or shingles. Then the bumps started moving.

A doctor found five active bot fly larvae living beneath the skin atop Dallas' head.

"I'd put my hand back there and feel them moving. I thought it was blood coursing through my head," Dallas told the (Glenwood Springs) Post Independent.

"I could hear them. I actually thought I was going crazy."

Dallas said he likely received the larval infestation while on a trip to Belize this summer. Bot fly infections are not uncommon in parts of Central and South America.

Adult bot flies are hairy and look like bees, without bristles. The larvae, which are about one-third the size of a penny, were living in a pit 2- to 3- millimeters wide. They were removed Thursday.

"It was weird and traumatic," said Dallas, of Carbondale. "I would get this pain that would drop me to my knees."

After a specialist told him he might have shingles, Dallas tried different creams and salves. But the pain only got worse.

"When I saw him again, it was pretty obvious something else was going on," said Dr. Kimball Spence, who could see the spots moving on Dallas' head. "There's an open pit. You see a little activity, not necessarily the larvae, but a fluctuation of the fluid in the pit."

Dallas' wife, Midge Dallas, teased him about it.

"I told him, 'I will love you through your maggots,'" she told the newspaper.

But Dallas saw little to laugh about.

"It's much funnier to everyone else," he said. "It makes my stomach turn over. It was cruel."